3-Methylcrotonate decarboxylase (MDC) variants

Abstract

Described herein are 3-methylcrotonate decarboxylase (MDC) variants that exhibit improved activity in converting 3-methylcrotonate to isobutylene, and methods of producing isobutylene using such enzyme variants.

Description

Technical Field

[0001] Described herein are 3-methylcrotonate decarboxylase (MDC) variants that exhibit improved activity in converting 3-methylcrotonate to isobutylene, and methods of producing isobutylene using such enzyme variants. Background Art

[0002] Many chemical compounds are currently derived from petrochemicals. Olefins, such as ethylene, propylene, the different butenes, or pentenes, are used in the plastics industry, for example to produce polypropylene or polyethylene, as well as in other areas of the chemical industry and in the fuel sector.

[0003] Butenes exist in four forms, one of which, isobutene (also known as isobutylene), enters the composition of methyl tert-butyl ether (MTBE), an antiknock additive for automotive fuels. Isobutene can also be used to produce isooctene, which in turn can be reduced to isooctane (2,2,4-trimethylpentane); the very high octane number of isooctane makes it an excellent fuel for so-called "gasoline" engines. Olefins such as isobutene are currently produced by catalytic cracking of petroleum products (or, in the case of hexene, derivation from coal or natural gas by the Fischer-Tropsch process). The production costs are therefore closely linked to the price of oil. In addition, catalytic cracking is often associated with considerable technical difficulties, which increase the process complexity and production costs.

[0004] In the context of sustainable industrial operations that meet the geochemical cycle, it is advocated to produce olefins such as isobutylene through biological pathways. Since fermentation and distillation processes already exist in the food processing industry, the first generation of biofuels is the fermentation production of ethanol. The production of second-generation biofuels is in the exploratory stage, which especially includes the production of long-chain alcohols (butanol and amyl alcohol), terpenes, paraffins and fatty acids. Two recent reviews provide a general overview of research in this field: Ladygina et al. (Process Biochemistry 41 (2006), 1001) and Wackett (Current Opinions in Chemical Biology 21 (2008), 187).

[0005] Different pathways for the enzymatic production of isobutene have been described previously; see, for example, Fujii et al. (Appl. Environ. Microbiol. 54 (1988), 583); Gogerty et al. (Appl. Environm. Microbiol. 76 (2010), 8004-8010), van Leeuwen et al. (Appl. Microbiol. Biotechnol. 93 (2012), 1377-1387) and WO2010 / 001078.

[0006] In addition to these pathways, there is an alternative pathway to provide isobutylene that utilizes a decarboxylation reaction to enzymatically convert 3-methylcrotonate to isobutylene. Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2).

[0007] The decarboxylation of 3-methylcrotonic acid has been proposed in US-A1-2009 / 0092975, but there is no experimental evidence for this conversion. In US-A1-2009 / 0092975, a nucleotide sequence called PAD1 from Saccharomyces cerevisiae is described, and its encoding decarboxylase is disclosed. The enzyme is proposed to be used in recombinant organisms as a selective marker, and describes that "weak acid" can be used as a selection agent. Many other acids such as 3-methylcrotonic acid are mentioned as potential "weak acids". However, it was later discovered that the above-mentioned PAD1 does not actually provide decarboxylase activity.

[0008] In fact, bacterial ubiD and ubiX or homologous eukaryotic fdc1 and pad1 genes have been mentioned to be involved in non-oxidative reversible decarboxylation. The combined action of phenylacrylic acid decarboxylase (PAD) and ferulic acid decarboxylase (FDC) is considered to be essential for the decarboxylation of phenylacrylic acid in Saccharomyces cerevisiae (J. Biosci. Bioeng. 109, (2010), 564-569; AMB Express, 5: 12 (2015) 1-5; ACS Chem. Biol. 10 (2015), 1137-1144).

[0009] Recently, the above enzyme family described as phenylacrylic acid decarboxylases (PADs) has been characterized as FMN prenyltransferases and no longer decarboxylases. It has been shown that Fdc1 (but not PAD) is uniquely responsible for this reversible decarboxylase activity and that it requires a novel cofactor, namely prenylated flavin synthesized by the related UbiX (or Pad1) protein. Thus, the true enzymatic activity of the PAD enzymes has been identified as the conversion of a flavin mononucleotide (FMN) cofactor with a prenyl moiety (from dimethylallyl-phosphate or pyrophosphate, called DMAP or DMAPP). This reaction is described in Figure 1A shown.

[0010] Therefore, contrary to the view of the prior art, the true decarboxylase is ferulic acid decarboxylase (FDC) in combination with modified FMN (prenylated FMN). Figure 1B As shown. This mechanism has recently been described for ferulic acid decarboxylase (FDC) associated with modified FMN (prenylated FMN) (the latter provided by PAD enzymes), involving a surprising enzymatic mechanism, namely, decarboxylation of α,β-unsaturated acids by 1,3-dipolar cycloaddition. In addition, the structure of this FDC decarboxylase has recently been elucidated (Nature 522 (2015), 497-501; Nature, 522 (2015), 502-505; Appl. Environ. Microbiol. 81 (2015), 4216-4223).

[0011] In addition, a method for producing isobutene has been previously described, comprising enzymatically converting 3-methylcrotonate into isobutene using the above-mentioned enzyme, wherein the corresponding enzyme is artificially implemented in the pathway that ultimately leads to the production of isobutene (WO 2017 / 085176). In WO 2017 / 085176, an FMN-dependent decarboxylase catalyzing the decarboxylation of 3-methylcrotonate to isobutene is described, which belongs to the 3-polyisopentenyl-4-hydroxybenzoate decarboxylase (UbiD) enzyme family, wherein in particular a UbiD enzyme derived from Hypocrea atroviridis has been described (UniProt accession number Q9NLP8).

[0012] Furthermore, improved variants of enzymes capable of converting 3-methylcrotonate into isobutene have also been described previously, wherein the above-mentioned FDC of Hypocrea atroviridis was used as a model enzyme (WO 2017 / 191239).

[0013] Although the above means and methods allow the production of isobutene from 3-methylcrotonic acid and meanwhile means and methods allowing increased production of isobutene from 3-methylcrotonic acid have been described, there is still a need for further improvements, in particular a need to further increase the efficiency of the process in order to make it more suitable for industrial purposes.

[0014] The present application meets this need by providing the embodiments defined in the claims. SUMMARY OF THE INVENTION

[0016] In a first aspect, the present invention provides variants of 3-methylcrotonate decarboxylase (MDC) which exhibit improved activity in converting 3-methylcrotonate to isobutylene relative to the corresponding MDC from which it is derived.

[0017] Improved enzyme variants or enzyme variants capable of catalyzing the reaction with increased activity are defined as enzyme variants that differ from the wild-type enzyme and catalyze the conversion of 3-methylcrotonic acid to isobutylene, such that the specific activity of the enzyme variant is higher than the specific activity of the wild-type enzyme for at least one given concentration of 3-methylcrotonic acid (preferably any 3-methylcrotonic acid greater than 0M to 1M). Specific activity is defined as the number of moles of substrate converted into moles of product per unit time by each mole of enzyme. cat (turnover number) is the specific activity at saturating concentration of substrate.

[0018] In particular, according to this first aspect, the present invention provides a method capable of generating a -3 s -1 An enzyme that converts 3-methylcrotonate to isobutylene with a conversion rate of 3-methylcrotonate to isobutylene of at least 2×10 -3 s -1 The conversion rate of 3-methylcrotonic acid to isobutylene is at least 4×10 -3 s -1 In the most preferred embodiment, the enzyme has a -3 s -1 or at least 1s -1 , or at least 10s -1 , even more preferably at least 100s -1 The conversion rate of 3-methylcrotonate to isobutylene is about 1×10 -3 s -1 The conversion rate of 3-methylcrotonic acid into isobutylene.

[0019] In the context of the present invention, "improved activity" means that the activity of the enzyme in question is at least 10%, preferably at least 20%, more preferably at least 30% or 50%, even more preferably at least 70% or 80%, particularly preferably at least 90% or 100% higher than the enzyme from which the variant is derived, preferably higher than the enzyme shown in SEQ ID NO: 1. In even more preferred embodiments, the improved activity may be at least 150%, at least 200%, at least 300%, at least 750% or at least 1000% higher than the activity of the corresponding enzyme from which the variant is derived (preferably the enzyme shown in SEQ ID NO: 1). In particularly preferred embodiments, the activity is measured by an assay using purified enzymes and chemically synthesized substrates, as described below. The improved activity of the variant can be measured as more isobutene produced under given conditions in a given time compared to the parent enzyme. This improved activity can result from a higher turnover number, for example a higher kcat value. It can also result from a lower Km value. It can also result from a higher kcat / Km value. Finally, it can result from a higher enzyme solubility or stability. The degree of improvement can be measured as an improvement in isobutene production. The degree of improvement may also be measured in terms of kcat improvement, kcat / Km improvement, or Km reduction, or in terms of soluble protein production or protein stability.

[0020] In another embodiment, the enzyme variant provided by the present invention is capable of converting 3-methylcrotonic acid into isobutylene, and the activity of the variant is at least 1.25 times as high as the conversion rate of the corresponding wild-type enzyme having the amino acid sequence shown in SEQ ID NO: 1. In a more preferred embodiment, the conversion rate (i.e., k) of the enzyme variant capable of converting 3-methylcrotonic acid into isobutylene is at least 1.25 times as high as the conversion rate of the corresponding wild-type enzyme having the amino acid sequence shown in SEQ ID NO: 1. cat The conversion rate of the amino acid sequence of the enzyme is at least 2 times, at least 3 times, at least 5 times or even at least 10 times as compared to the conversion rate of the corresponding wild-type enzyme having the amino acid sequence as shown in SEQ ID NO: 1. In an even more preferred embodiment, the conversion rate is at least 100 times or even at least 500 times as compared to the corresponding wild-type enzyme having the amino acid sequence as shown in SEQ ID NO: 1.

[0021] Such enzyme variants are obtained by mutating at specific positions in the amino acid sequence of MDC, and the variants obtained by making such mutations show improved activity in catalyzing the conversion of 3-methylcrotonic acid into isobutylene. The activity of the enzyme capable of converting 3-methylcrotonic acid into isobutylene can be determined by methods known to those skilled in the art. In one embodiment, the activity is determined as described in the examples attached herein. In a specific embodiment, the activity can be measured by incubating the enzyme in vitro, preferably a cell lysate containing an overexpressed recombinant protein. Alternatively, a purified enzyme can be used or an in vivo assay can be used.

[0022] More specifically, the activity of the MDC variants in converting 3-methylcrotonic acid to isobutylene can be evaluated in an enzymatic in vitro assay based on purified protein and detection of isobutylene by gas chromatography. The conversion rate of the enzyme to be evaluated can be examined as follows: The Michaelis-Menten k for the reaction of 3-methylcrotonic acid to isobutylene can be determined using the following protocol: cat and K m Steady-state kinetic constant:

[0023] The enzymatic assay for quantifying the conversion of 3-methylcrotonate to isobutylene was performed in 50 mM potassium phosphate pH 7.5 buffer, 20 mM NaCl, 3 mM MgCl2, 5 mM DTT, 0.5 mg / ml purified enzyme of the MDC variant to be tested, 100 μl of lysate containing FMN prenyltransferase (i.e., flavin prenyltransferase UbiX protein from E. coli expressed and prepared as further described below), and different concentrations (ranging from 0-128 mM) of the substrate 3-methylcrotonate in 2 ml glass vials at 30°C. A control without MDC enzyme was performed in parallel. After 60 minutes, the reaction was terminated by incubation at 80°C for 2 minutes. The rate of isobutylene production was quantified by gas chromatography as follows.

[0024] The isobutylene formed in the reaction headspace was analyzed by gas chromatography (GC) equipped with a flame ionization detector (FID). For GC headspace analysis, 1 ml of headspace gas was separated using an isothermal mode at 130°C in a Bruker GC-450 system equipped with a GS-alumina column (30m×0.53mm) (Agilent). Nitrogen was used as a carrier gas with a flow rate of 6 ml / min. The enzymatic reaction products were identified by comparison with an isobutylene standard. Under these GC conditions, the retention time of isobutylene was 2.42 minutes. From the isobutylene production rate, the enzyme catalytic efficiency can be calculated using the Michaelis-Menten approximation. The isobutylene production rate (PV moles / mole enzyme / second) was plotted as a function of the 3-methylcrotonic acid concentration and the Michaelis Menten equation (V=(V max *(substrate)) / (K m +(substrate))) fitting curve to deduce k cat Value(s) -1 ) and K m Value (mM).

[0025] The MDC variants to be tested can be provided according to the following scheme: The MDC to be tested is subcloned into the pETDuetTM-1 co-expression vector. The vector contains a stretch of 6 histidine codons after the methionine start codon of ferulic acid decarboxylase to provide an affinity tag for purification.

[0026] According to the standard heat shock protocol, competent E. coli BL21 (DE3) cells (Novagen) were transformed with the vector and plated on LB agar plates supplemented with appropriate antibiotics. Cells were grown overnight at 30 ° C until each colony reached the desired size. Then single colonies were picked and transferred to 5 ml of liquid LB medium supplemented with appropriate antibiotics. Cells were grown at 30 ° C for 16 hours. ZYM-5052 autoinduction medium (Studier FW, Prot. Exp. Pur. 41, (2005), 207-234) was used to inoculate the LB culture medium of the transformed cells, and the culture was shaken and grown (160 rpm) at 30 ° C for 24 hours. Cells were collected by centrifugation at 4 ° C, 10,000 rpm for 20 minutes, and the precipitate was frozen and stored at -80 ° C. The overexpressed protein pellet containing 500 ml of cultured cells was melted on ice and resuspended in 15 ml of 50 mM potassium phosphate buffer containing 200 mM NaCl, 10 mM MgCl2, 10 mM imidazole and 1 mM DTT. 20 microliters of LYSONASE (Novagen) were added, and the cells were incubated at room temperature for 10 minutes and then returned to ice for 20 minutes. Cell lysis was then completed by 2×15 seconds of ultrasonic treatment.

[0027] The bacterial extract was then clarified by centrifugation at 4000 rpm for 40 minutes at 4°C. The clarified bacterial lysate was loaded onto a PROTINO-2000 Ni-TED column (Macherey-Nagel) to allow adsorption of the 6-His-tagged protein. The column was washed and the target enzyme was eluted with 6 ml of 50 mM potassium phosphate buffer containing 250 mM imidazole. The eluate was then concentrated, desalted on an Amicon Ultra-4 10 kDa filter unit (Millipore), and the enzyme was resuspended in 50 mM potassium phosphate buffer containing 1 mM DTT and 20 mM NaCl. Protein concentration was determined by direct UV 280 nm measurement on a NanoDrop 1000 spectrophotometer (Thermo Scientific) or by Bradford determination (BioRad).

[0028] Accordingly, the cDNA of the flavin isopentenyltransferase UbiX protein from Escherichia coli was cloned, recombinantly expressed, purified and quantified.

[0029] As described above in the enzymatic in vitro assay for determining the activity of the MDC variants of the invention, UbiX need not necessarily be provided in the form of recombinant expression and subsequent purification. Therefore, UbiX can also be provided in the form of a cell lysate containing UbiX without purification, as described below.

[0030] The flavin isoprenyltransferase UbiX protein from Escherichia coli was cloned into the vector pCAN. The flavin isoprenyltransferase UbiX protein from Escherichia coli was purchased from NAIST (Nara Institute of Science and Technology, Japan, ASKA collection).

[0031] According to the standard heat shock protocol, competent E. coli BL21 (DE3) cells (Novagen) were transformed with the vector and plated on LB agar plates supplemented with appropriate antibiotics. Cells were grown overnight at 30°C until each colony reached the desired size. Then single colonies were picked and transferred to 5 ml of liquid LB medium supplemented with appropriate antibiotics. Cells were grown with shaking at 30°C for 16 hours. The LB culture of the transformed cells was inoculated with ZYM-5052 autoinduction medium (Studier FW, Prot. Exp. Pur. 41, (2005), 207-234), and the culture was grown with shaking at 30°C (160 rpm) for 24 hours. Cells were collected by centrifugation at 4°C, 10,000 rpm for 20 minutes, and the precipitate was stored at -80°C. The pellet of 500 ml cultured cells was melted on ice and resuspended in 15 ml of 50 mM potassium phosphate buffer containing 200 mM NaCl, 10 mM MgCl2, 10 mM imidazole and 1 mM DTT. 20 microliters of LYSONASE (Novagen) were added. The cells were incubated at room temperature for 10 minutes and then returned to ice for 20 minutes. Cell lysis was completed by 2×15 second ultrasonic treatment. The cell lysate containing UbiX protein was kept on ice.

[0032] As an alternative to the above-described in vitro assay, the activity of the MDC variants in converting 3-methylcrotonate to isobutylene can be evaluated by an in vivo test. This coupled in vivo test is based on the use of a bacterial strain transformed with an expression vector containing the coding sequence leading to the production of the MDC variant and the flavin isopentenyltransferase UbiX protein from Escherichia coli (SEQ ID NO: 2). Therefore, in addition to the cDNA of the flavin isopentenyltransferase UbiX protein from Escherichia coli, the MDC variant to be tested is subcloned into the pETDuet TM -1 co-expression vector (Novagen).

[0033] The MDC variants of the invention to be tested were used to catalyze the decarboxylation of 3-methylcrotonate to isobutylene, while the flavin isopentenyltransferase UbiX protein from E. coli provided the modified flavin cofactor. Therefore, in a coupled in vivo assay, a bacterial strain was used, which was transformed with the above-mentioned expression vector.

[0034] First, the transformed bacterial strain is plated on the LB agar plate supplemented with appropriate antibiotic. Then the cells are grown overnight at 30 ℃ until each bacterium colony reaches the required size. Then pick a single bacterium colony and transfer to 50 or 500 μ L of liquid LB medium supplemented with appropriate antibiotics separately. The cell was shaken and grown for 20 hours at 30 ℃. LB culture is used to inoculate the 300 μ L of the self-induction medium supplemented with appropriate antibiotics in 384-well deep-well microplates or inoculate the self-induction medium supplemented with appropriate antibiotics in 1 mL in 96-well deep-well microplates (Studier FW, Prat. Exp. Pur. 41, (2005), 207-234), and in a shaking incubator set to 700 rpm and 85% humidity, grown for 24 hours at 30 ℃, to produce two types of recombinases. The cell pellet containing these overexpressed recombinant enzymes was then resuspended in 40 μL of minimal medium (pH 7.5, 100 mM phosphate, 10 g.L glucose) in a 384-deep-well microplate. -1 , MgSO4 1mM) supplemented with 10mM 3-methylcrotonic acid; or resuspended in 400μL basic medium (pH 7.5, phosphate 100mM, glucose 10g.L) in a 96-deep-well microplate. -1 , MgSO41mM), supplemented with 10mM 3-methylcrotonic acid, and incubated in a shaking incubator at 37°C, 700 rpm for another 2 or 4 hours. In this step, the MDC variant catalyzes the decarboxylation of 3-methylcrotonic acid to isobutylene. After inactivation at 80°C for 5 minutes, the isobutylene produced is quantified by gas chromatography as follows. 100 μL of headspace gas from each enzymatic reaction is injected into a Brucker GC-450 system equipped with a flame ionization detector (FID). The compounds present in the sample are separated by chromatography using an RTX-1 column at 100°C with a constant flow of 1 mL / min of nitrogen as the carrier gas. After injection, the peak area of ​​isobutylene is calculated.

[0035] By providing the above enzyme variants, the present invention allows significantly improving the production efficiency of isobutylene from 3-methylcrotonic acid.

[0036] The term "3-methylcrotonate decarboxylase (MDC)" refers to an enzyme that can catalyze the decarboxylation of 3-methylcrotonate to isobutylene. Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide. The activity can be measured by methods known in the art and as described above. In a preferred embodiment, the MDC is a ferulic acid decarboxylase (FDC) or is derived from such an enzyme. FDC belongs to the enzyme class EC 4.1.1.-. As described above, FDC in combination with modified FMN (prenylated-FMN) was initially described as being able to catalyze the decarboxylation of α,β-unsaturated, more specifically, catalyze the decarboxylation of 3-methylcrotonate to isobutylene by 1,3-dipolar cycloaddition. Therefore, in the context of the present invention, the term FDC relates to an enzyme that can catalyze the decarboxylation of 3-methylcrotonate to isobutylene, preferably when provided with prenylated FMN.

[0037] For example, FDC enzymes have been described in Saccharomyces cerevisiae, Enterobacter sp., Bacillus pumilus, Aspergillus niger or Candida dubliniensis. Thus, in a preferred embodiment, the FDC is derived from Saccharomyces cerevisiae (Uniprot Accession No. Q03034), Enterobacter sp. (Uniprot Accession No. V3P7U0), Bacillus pumilus (Uniprot Accession No. Q45361), Aspergillus niger (Uniprot Accession No. A2R0P7) or Candida dubliniensis (Uniprot Accession No. B9WJ66). In a more preferred embodiment, the FDC is 3-polyisopentenyl-4-hydroxybenzoate decarboxylase (UbiD). 3-Polyisopentenyl-4-hydroxybenzoate decarboxylases have been described, for example, in Hypocrea atroviridis, Sphaerulina musiva, Penecillinum requeforti, Fusarium oxysporum f. sp. Lycopersici, Saccharomyces kudriavzevii, Saccharomyces cerevisiae, Aspergillus parasiticus, Candida albicans, Grosmannia clavigera, Escherichia coli, Bacillus megaterium, Methanothermobacter sp. Cat2 or Mycobacterium chelonae 1518.Thus, in a more preferred embodiment, the FDC enzyme variant capable of catalyzing the decarboxylation of 3-methylcrotonate to isobutene is derived from Hypocrea atroviridis (UniProt Accession No. G9NLP8), Sphaerulina musiva (UniProt Accession No. M3DF95), Penecillinum requeforti (UniProt Accession No. W6QKP7), Fusarium oxysporum f.sp. Lycopersici (UniProt Accession No. W9LTH3), Saccharomyces cerevisiae, Aspergillus parasiticus, Candida albicans, Grosmannia clavigera, Escherichia coli (Uniprot Accession No. P0AAB4), Bacillus megaterium (Uniprot Accession No. D5DTL4), Methanothermobacter sp.CaT2 (Uniprot Accession No. T2GKK5) or Mycobacterium chelonae (UniProt Accession No. T2GKK5). Preferably, the MDC is an enzyme associated with and / or dependent on an FMN prenyltransferase. As described above, the enzymatic conversion of 3-methylcrotonate to isobutylene using an FMN-dependent decarboxylase is preferably associated with an FMN prenyltransferase and relies on a reaction of two consecutive steps catalyzed by two enzymes, namely an FMN-dependent decarboxylase (catalyzing the actual decarboxylation of 3-methylcrotonate to isobutylene) and an associated FMN prenyltransferase (which provides a modified flavin cofactor). The flavin cofactor may preferably be FMN or FAD. FMN (flavin mononucleotide; also known as riboflavin-5'-phosphate) is a biomolecule produced by the enzyme, riboflavin kinase, from riboflavin (vitamin B2), and acts as a prosthetic group for various reactions. FAD (flavin adenine dinucleotide) is a redox cofactor, more specifically a prosthetic group, involved in several important reactions in metabolism. The FMN prenyltransferase that may be associated with the MDC variants of the present invention is described in further detail below.

[0038] The present invention now provides improved variants of enzymes capable of converting 3-methylcrotonate into isobutene. The inventors used FDC, more specifically the UbiD-like decarboxylase of Streptomyces sp. 769 shown in SEQ ID NO: 1 (UniProt accession number A0A0A8EV26; corresponding encoding gene GZL_07100), as a model enzyme and demonstrated that variants of this enzyme can be provided which show increased activity in converting 3-methylcrotonate into isobutene.

[0039] The model enzyme used by the present inventors, namely the UbiD-like decarboxylase of Streptomyces sp. 769, has the amino acid sequence shown in SEQ ID NO:1.

[0040] In a preferred embodiment, the variants of the present invention are characterized in that they are derived from MDC, more preferably from MDC having the amino acid sequence shown in SEQ ID NO: 1 or a highly related sequence (at least 63% identical), wherein a mutation is made at one or more of the following positions, whereby they show the ability to convert 3-methylcrotonic acid into isobutylene, and they can do this with improved activity. In a preferred embodiment, the variants of the present invention are derived from a sequence showing at least 70%, more preferably at least 80% sequence identity with SEQ ID NO: 1, and wherein one or more substitutions and / or deletions and / or insertions have been made at the positions indicated herein.

[0041] However, the teachings of the present invention are not limited to the MDC enzyme of Streptomyces sp. 769 shown in SEQ ID NO: 1, which has been used as a model enzyme, but can be extended to MDC enzymes from other organisms or enzymes structurally related to SEQ ID NO: 1, e.g., truncated variants of the enzyme. Thus, the present invention also relates to variants of MDC that are structurally related to the Streptomyces sp. 769 sequence (SEQ ID NO: 1) and that exhibit one or more substitutions and / or deletions and / or insertions at positions corresponding to any position as shown herein. The term "structurally related" refers to an MDC that exhibits at least n% sequence identity to the sequence shown in SEQ ID NO: 1, wherein n is an integer between 60-100, preferably 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99. In a preferred embodiment, the structurally related MDC is from bacteria, more preferably from an organism of the phylum Actinomycetes, even more preferably from an organism of the class Actinomycetes, the order Actinomycetales, the family Streptomycetaceae or a species of the genus Streptomyces, most preferably a species of Streptomyces 769.

[0042] 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99.

[0043] In a more preferred embodiment, the MDC variant of the present invention has or is preferably derived from a sequence that is at least n% identical to SEQ ID NO: 1, n is preferably 63, 64, 74, 77, 78, 94 or 97, and it has one or more substitutions and / or one or more deletions and / or one or more insertions at the positions as indicated herein.

[0044] When the sequences compared do not have the same length, the degree of identity refers to the percentage of amino acid residues in the shorter sequence that are identical to the amino acid residues in the longer sequence, or refers to the percentage of amino acid residues in the longer sequence that are identical to the amino acid residues in the shorter sequence. Preferably, it refers to the percentage of amino acid residues in the shorter sequence that are identical to the amino acid residues in the longer sequence. The degree of sequence identity can be determined according to methods well known in the art, preferably using a suitable computer algorithm (such as CLUSTAL).

[0045] When using the Clustal analysis method to determine whether a particular sequence is, for example, at least 60% identical to a reference sequence, the default settings can be used, or for amino acid sequence comparisons, the settings are preferably as follows: matrix: blosum 30; open gap penalty: 10.0; extension gap penalty: 0.05; delayed divergence: 40; gap separation distance: 8. For nucleotide sequence comparisons, the extension gap penalty is preferably set to 5.0.

[0046] In a preferred embodiment, ClustalW2 is used for the comparison of amino acid sequences. In the case of a pairwise comparison / alignment, the following settings are preferably selected: protein weight matrix: BLOSUM 62; Gap opening: 10; Gap extension: 0.1. In the case of a multiple comparison / alignment, the following settings are preferably selected: protein weight matrix: BLOSUM 62; Gap opening: 10; Gap extension: 0.2; Gap distance: 5; No terminal gaps. Preferably, the degree of identity is calculated over the entire length of the sequence.

[0047] The amino acid residues at positions corresponding to the positions as indicated herein in the amino acid sequence shown in SEQ ID NO: 1 can be identified by methods known in the art by those skilled in the art. For example, such amino acid residues can be identified by aligning the sequence in question with the sequence shown in SEQ ID NO: 1 and by determining the positions corresponding to the following positions of SEQ ID NO: 1. The alignment can be performed using means and methods known to those skilled in the art, for example by using known computer algorithms such as the Lipman-Pearson method (Science 227 (1985), 1435) or the CLUSTAL algorithm. Preferably, in such an alignment, the maximum homology is designated as the presence of conserved amino acid residues in the amino acid sequence.

[0048] In a preferred embodiment, ClustalW2 is used for the comparison of amino acid sequences. In the case of a pairwise comparison / alignment, the following settings are preferably selected: protein weight matrix: BLOSUM 62; Gap opening: 10; Gap extension: 0.1. In the case of a multiple comparison / alignment, the following settings are preferably selected: protein weight matrix: BLOSUM 62; Gap opening: 10; Gap extension: 0.2; Gap distance: 5; No terminal gaps.

[0049] When the amino acid sequences of MDCs are aligned by this method, the positions of the corresponding amino acid residues can be determined in each MDC regardless of the presence of insertions or deletions in the amino acid sequences.

[0050] In the context of the present invention, "replacing with another amino acid residue" means that the corresponding amino acid residue at the indicated position can be replaced with any other possible amino acid residue, for example, a naturally occurring amino acid or a non-naturally occurring amino acid (Brustad and Arnold, Curr. Opin. Chem. Biol. 15 (2011), 201-210), preferably with an amino acid residue selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine and valine. Preferred replacements for certain positions are further indicated below. In addition, the term "substituted" or "replacement" also means that the corresponding amino acid residue at the indicated position is modified.

[0051] Such modifications include naturally occurring modifications and non-naturally occurring modifications. Naturally occurring modifications include, but are not limited to, eukaryotic post-translational modifications, such as attachment of functional groups (e.g., acetate, phosphate, hydroxyl groups, lipids (myristoylation of glycine residues), and carbohydrates (e.g., glycosylation of arginine, asparagine, etc.). Naturally occurring modifications also encompass chemical structural changes caused by citrullination, carbamylation, and disulfide bond formation between cysteine ​​residues; attachment of cofactors (FMN or FAD that may be covalently attached) or attachment of peptides (e.g., ubiquitination or SUMOylation).

[0052] Non-naturally occurring modifications include, for example, in vitro modifications such as biotinylation of lysine residues or inclusion of non-canonical amino acids (see Liu and Schultz, Annu. Rev. Biochem. 79 (2010), 413-44 and Wang et al., Chem. Bio. 2009 March 27; 16(3), 323-336; doi: 101016 / jchembiol.2009.03.001).

[0053] In the context of the present invention, "deleted" or "deletion" means that the amino acid at the corresponding position is deleted.

[0054] In the context of the present invention, "inserted" or "insertion" means the insertion of one or two, preferably one, amino acid residues at the corresponding position, preferably before the indicated position.

[0055] In a second aspect, the present invention provides a variant of 3-methylcrotonate decarboxylase (MDC), which exhibits an improved activity for converting 3-methylcrotonate into isobutylene relative to the corresponding MDC from which it is derived, wherein the MDC variant is characterized in that it exhibits one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions are at one or more positions corresponding to SEQ ID It appears at positions corresponding to positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462 and 473 of the amino acid sequence shown in NO:1.

[0056] A preferred embodiment of the present invention relates to an MDC variant having an amino acid sequence as shown in SEQ ID NO: 1 or an amino acid sequence having at least 63% sequence identity with SEQ ID NO: 1, wherein in the 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462 and 473 in the amino acid sequence shown in NO: 1, or one or more amino acid residues at positions corresponding to any of these positions are substituted by another amino acid residue or deleted, or have been inserted at one or more of these positions, and wherein the MDC variant has improved activity in converting 3-methylcrotonic acid to isobutylene.

[0057] Therefore, a preferred embodiment of the present invention relates to 3-methylcrotonate decarboxylase (MDC) variants showing improved activity in converting 3-methylcrotonate to isobutylene relative to the MDC of SEQ ID NO: 1,

[0058] wherein said variant is characterized by:

[0059] An amino acid sequence having at least 63% sequence identity to SEQ ID NO: 1; and

[0060] At positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462 and 473 in the amino acid sequence of SEQ ID NO: 1, or at positions corresponding to any of these positions, one or more amino acid residues are substituted by another amino acid residue, deleted or inserted.

[0061] A preferred embodiment of the present invention relates to an MDC variant having an amino acid sequence as shown in SEQ ID NO: 1, or an amino acid sequence having at least 63% sequence identity with SEQ ID NO: 1, wherein at positions 406, 198, 240, 390, 402, 408 and 449 in the amino acid sequence as shown in SEQ ID NO: 1, or at positions corresponding to any of these positions, one or more amino acid residues are substituted by another amino acid residue or deleted, or insertions have been made at one or more of these positions, and wherein the MDC variant has improved activity in converting 3-methylcrotonic acid into isobutylene.

[0062] Therefore, a preferred embodiment of the present invention relates to 3-methylcrotonate decarboxylase (MDC) variants showing improved activity in converting 3-methylcrotonate to isobutylene relative to the MDC of SEQ ID NO: 1,

[0063] wherein said variant is characterized by:

[0064] An amino acid sequence having at least 63% sequence identity to SEQ ID NO: 1; and

[0065] At positions 406, 198, 240, 390, 402, 408 and 449 in the amino acid sequence of SEQ ID NO: 1, or at positions corresponding to any of these positions, one or more amino acid residues are substituted, deleted or inserted by another amino acid residue.

[0066] According to one embodiment, the present invention relates to any of the above-mentioned MDC variants, which have an amino acid sequence as shown in SEQ ID NO: 1, or an amino acid sequence having at least 63% sequence identity with SEQ ID NO: 1, wherein

[0067] (1) the amino acid residue at position 198 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with glutamine or tryptophan; and / or

[0068] (2) the amino acid residue at position 240 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with isoleucine or asparagine; and / or

[0069] (3) the amino acid residue at position 390 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with serine, aspartic acid, leucine, asparagine or glutamine; and / or

[0070] (4) the amino acid residue at position 402 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with alanine; and / or

[0071] (5) the amino acid residue at position 406 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with glycine, alanine or serine; and / or

[0072] (6) the amino acid residue at position 408 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with isoleucine, alanine, cysteine, leucine or methionine; and / or

[0073] (7) the amino acid residue at position 449 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with isoleucine, methionine or valine; and / or

[0074] (8) the amino acid residue at position 25 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with glutamic acid; and / or

[0075] (9) the amino acid residue at position 35 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with isoleucine; and / or

[0076] (10) the amino acid residue at position 36 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with tyrosine; and / or

[0077] (11) the amino acid residue at position 74 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with valine; and / or

[0078] (12) the amino acid residue at position 80 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with serine; and / or

[0079] (13) the amino acid residue at position 86 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with asparagine or tyrosine; and / or

[0080] (14) the amino acid residue at position 126 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with valine; and / or

[0081] (15) the amino acid residue at position 129 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with valine; and / or

[0082] (16) the amino acid residue at position 166 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with aspartic acid; and / or

[0083] (17) the amino acid residue at position 196 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with isoleucine; and / or

[0084] (18) the amino acid residue at position 204 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with arginine or serine; and / or

[0085] (19) the amino acid residue at position 208 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with leucine; and / or

[0086] (20) the amino acid residue at position 236 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with leucine or valine; and / or

[0087] (21) the amino acid residue at position 237 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with alanine, aspartic acid, asparagine or proline; and / or

[0088] (22) the amino acid residue at position 238 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with histidine, arginine, serine or tryptophan; and / or

[0089] (23) the amino acid residue at position 298 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with serine; and / or

[0090] (24) the amino acid residue at position 302 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, cysteine, phenylalanine, lysine, methionine, glutamine, arginine or serine; and / or

[0091] (25) the amino acid residue at position 359 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with cysteine ​​or valine; and / or

[0092] (26) the amino acid residue at position 366 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with isoleucine or phenylalanine; and / or

[0093] (27) the amino acid residue at position 368 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with isoleucine or methionine; and / or

[0094] (28) the amino acid residue at position 395 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with cysteine, glutamic acid or valine; and / or

[0095] (29) the amino acid residue at position 396 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with isoleucine; and / or

[0096] (30) the amino acid residue at position 407 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, cysteine, isoleucine, lysine, arginine, serine or threonine; and / or

[0097] (31) the amino acid residue at position 426 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with valine; and / or

[0098] (32) the amino acid residue at position 450 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, histidine, methionine, asparagine, glutamine, serine or valine; and / or

[0099] (33) the amino acid residue at position 451 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with asparagine or serine; and / or

[0100] (34) the amino acid residue at position 452 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with phenylalanine; and / or

[0101] (35) the amino acid residue at position 454 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, aspartic acid, glycine, histidine, lysine, leucine, methionine, glutamine, arginine, serine, threonine, valine or tryptophan; and / or

[0102] (36) the amino acid residue at position 455 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, glutamic acid, histidine, lysine, asparagine, serine or valine; and / or

[0103] (37) the amino acid residue at position 456 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with glutamine; and / or

[0104] (38) the amino acid residue at position 457 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with lysine; and / or

[0105] (39) the amino acid residue at position 458 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with glutamic acid, phenylalanine, glycine, leucine, methionine, asparagine, glutamine, arginine, serine or tyrosine; and / or

[0106] (40) the amino acid residue at position 462 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with cysteine ​​or valine; and / or

[0107] (41) The amino acid residue at position 473 of the amino acid sequence shown in SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with serine.

[0108] The present invention also relates to variants as defined in (1) to (41) above, wherein the amino acid residue replacing the amino acid residue at the position in SEQ ID NO: 1 is not the specific amino acid residue but a conservative amino acid residue relative to the indicated substituted amino acid.

[0109] Whether a certain amino acid is conservative with respect to another amino acid can be determined according to means and methods known in the art and as described above. One possible means and method is the PAM 250 matrix; or Blosum Family Matrices can be used.

[0110] According to another embodiment, the present invention relates to any of the above-mentioned MDC variants, wherein in the variant, at 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, At positions 446, 447, 448, 453, 459, 460, 461, 479 and 496, or at positions corresponding to any of these positions, one or more other amino acid residues are substituted by another amino acid residue or are deleted, or wherein an insertion has been made at one or more of these positions, and wherein the MDC has improved activity in converting 3-methylcrotonic acid to isobutylene relative to the corresponding MDC from which it is derived.

[0111] Therefore, another embodiment of the present invention relates to any of the above variants, wherein the variant is characterized in that it is selected from the group consisting of SEQ ID 479, 480, 491, 504, 512, 524, 536, 548, 552, 564, 572, 576, 581, 582, 583, 584, 586, 587, 591, 604, 612, 624, 630, 640, 650, 660, 670, 680, 691, 705, 710, 711, 712, 713, 714, 715, 716, 717, 718, 720, 721, 722, 723, 724, 725, 726, 727, 728, 729, 730, 731, 732, 733, 734, 735

[0112] According to one embodiment, the present invention relates to any of the above-mentioned MDC variants, which are selected from the group consisting of 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 456, 457, 461, 462, 463, 464, 465, 466, 467, 468, 470, 471, 472, 473, 474, 475, 476, 477, 478, 479, 480, 481, 482, 483, 484, 485, 486, 487, 488, 489, 490, 501 at positions 46, 447, 448, 453, 459, 460, 461, 479 and 496, or at positions corresponding to any of these positions, one or more other amino acid residues are substituted by another amino acid residue or are deleted, or insertions have been made at one or more of these positions, and wherein the MDC has improved activity in converting 3-methylcrotonic acid to isobutylene relative to the corresponding MDC from which it is derived, wherein

[0113] (42) the amino acid residue at position 85 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with leucine; and / or

[0114] (43) the amino acid residue at position 241 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with aspartic acid, asparagine or valine; and / or

[0115] (44) the amino acid residue at position 401 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with tyrosine; and / or

[0116] (45) the amino acid residue at position 403 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, cysteine, glycine, histidine, isoleucine, asparagine, proline, glutamine, arginine or valine; and / or

[0117] (46) the amino acid residue at position 404 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with phenylalanine, leucine or methionine; and / or

[0118] (47) the amino acid residue at position 405 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with histidine, isoleucine, methionine, threonine or valine; and / or

[0119] (48) the amino acid residue at position 443 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, aspartic acid, phenylalanine, histidine, leucine, asparagine, arginine, serine, tryptophan or tyrosine; and / or

[0120] (49) the amino acid residue at position 444 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, glutamic acid, phenylalanine, histidine, isoleucine, leucine, glutamine or threonine; and / or

[0121] (50) the amino acid residue at position 445 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with leucine, alanine, cysteine, serine or threonine; and / or

[0122] (51) the amino acid residue at position 446 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, cysteine, phenylalanine, isoleucine, methionine, asparagine, serine or valine; and / or

[0123] (52) the amino acid residue at position 448 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with phenylalanine, tryptophan or tyrosine; and / or

[0124] (53) the amino acid residue at position 2 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at the position corresponding to this position is deleted or substituted with asparagine; and / or

[0125] (54) the amino acid residue at position 3 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at the position corresponding to this position is deleted or substituted with leucine or methionine; and / or

[0126] (55) the amino acid residue at position 5 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at the position corresponding to this position is deleted or substituted with isoleucine; and / or

[0127] (56) the amino acid residue at position 6 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at the position corresponding to this position is deleted or substituted with methionine; and / or

[0128] (57) the amino acid residue at position 24 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with alanine, aspartic acid, leucine or valine; and / or

[0129] (58) the amino acid residue at position 64 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with histidine; and / or

[0130] (59) the amino acid residue at position 66 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with histidine; and / or

[0131] (60) the amino acid residue at position 154 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with aspartic acid; and / or

[0132] (61) the amino acid residue at position 168 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with valine; and / or

[0133] (62) the amino acid residue at position 175 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with glutamic acid; and / or

[0134] (63) the amino acid residue at position 195 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with isoleucine or valine; and / or

[0135] (64) the amino acid residue at position 197 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with valine; and / or

[0136] (65) the amino acid residue at position 214 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with threonine; and / or

[0137] (66) the amino acid residue at position 277 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with tyrosine; and / or

[0138] (67) the amino acid residue at position 296 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with glutamine; and / or

[0139] (68) the amino acid residue at position 305 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with isoleucine or threonine; and / or

[0140] (69) the amino acid residue at position 339 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with histidine; and / or

[0141] (70) the amino acid residue at position 343 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with serine; and / or

[0142] (70) the amino acid residue at position 347 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with cysteine; and / or

[0143] (72) the amino acid residue at position 349 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with methionine or serine; and / or

[0144] (73) the amino acid residue at position 350 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with serine; and / or

[0145] (74) the amino acid residue at position 363 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with glycine; and / or

[0146] (75) the amino acid residue at position 391 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with aspartic acid or tryptophan; and / or

[0147] (76) the amino acid residue at position 394 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with cysteine, aspartic acid, glutamine or threonine; and / or

[0148] (77) the amino acid residue at position 398 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with cysteine ​​or arginine; and / or

[0149] (78) the amino acid residue at position 439 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with cysteine; and / or

[0150] (79) the amino acid residue at position 440 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with leucine; and / or

[0151] (80) the amino acid residue at position 441 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with glycine, histidine, lysine, asparagine, proline, arginine, serine or threonine; and / or

[0152] (81) the amino acid residue at position 442 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, cysteine, glutamic acid, glycine, histidine, leucine, methionine, asparagine, glutamine, arginine, serine or threonine; and / or

[0153] (82) the amino acid residue at position 447 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with glutamine; and / or

[0154] (83) the amino acid residue at position 453 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with cysteine, glycine, leucine, asparagine, proline, arginine or serine; and / or

[0155] (84) the amino acid residue at position 459 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with aspartic acid, glutamic acid, glycine, methionine, asparagine, glutamine, arginine, threonine or tyrosine; and / or

[0156] (85) the amino acid residue at position 460 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with glutamic acid, phenylalanine, glycine, leucine, methionine, asparagine, glutamine or arginine; and / or

[0157] (86) the amino acid residue at position 461 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with alanine, glycine, leucine, methionine, glutamine, serine or valine; and / or

[0158] (87) the amino acid residue at position 479 of the amino acid sequence of SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted, or is substituted with cysteine, isoleucine, leucine, methionine, serine, threonine or valine; and / or

[0159] (88) The amino acid residue at position 496 of the amino acid sequence shown in SEQ ID NO: 1 or the amino acid residue at a position corresponding to this position is deleted or substituted with leucine.

[0160] The present invention also relates to variants as defined in (42) to (88) above, wherein the amino acid residue replacing the amino acid residue at the position in SEQ ID NO: 1 is not the specific amino acid residue but a conservative amino acid residue relative to the indicated substituted amino acid.

[0161] Whether a certain amino acid is conservative with respect to another amino acid can be determined according to means and methods known in the art and as described above. One possible means and method is the PAM 250 matrix; or Blosum Family Matrices can be used.

[0162] Another preferred embodiment of the present invention relates to 3-methylcrotonate decarboxylase (MDC) variants showing improved activity in converting 3-methylcrotonate to isobutylene relative to the MDC of SEQ ID NO: 1,

[0163] wherein said variant is characterized by:

[0164] An amino acid sequence having at least 78% sequence identity to SEQ ID NO: 1; and

[0165] At positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462 and 473 in the amino acid sequence of SEQ ID NO: 1, or at positions corresponding to any of these positions, one or more amino acid residues are substituted by another amino acid residue, deleted or inserted.

[0166] Regarding preferred embodiments for substitutions, deletions or insertions of these variants, the above description applies. Thus, in preferred embodiments, the changes made at any of the above positions in these variants are substitutions, deletions and / or insertions as defined above.

[0167] Another preferred embodiment of the present invention relates to any of the above variants, which have an amino acid sequence with at least 78% sequence identity to SEQ ID NO: 1, wherein the variant is characterized in that it is selected from SEQ ID NO: 479, 480, 491, 504, 512, 524, 536, 548, 552, 564, 572, 576, 581, 582, 583, 584, 586, 587, 591, 604, 612, 624, 630, 640, 650, 660, 670, 680, 691, 705, 710, 711, 712, 713, 714, 715, 716, 717, 718, 720, 721, 722, 723, 724, 725, 726, 727, 728, 729, 730, 731, 732, 733, 734, 735

[0168] Regarding preferred embodiments for substitutions, deletions or insertions of these variants, the above description applies. Thus, in preferred embodiments, the changes made at any of the above positions in these variants are substitutions, deletions and / or insertions as defined above.

[0169] Another preferred embodiment of the present invention relates to 3-methylcrotonate decarboxylase (MDC) variants showing improved activity in converting 3-methylcrotonate to isobutylene relative to the MDC of SEQ ID NO: 1,

[0170] wherein said variant is characterized by:

[0171] It has an amino acid sequence that is at least 77% identical to SEQ ID NO: 1; and

[0172] It shows that one or more amino acid residues are substituted, deleted or inserted by another amino acid residue at positions 25, 74, 80, 166, 196, 198, 204, 208, 236, 237, 238, 240, 302, 366, 368, 390, 395, 402, 406, 407, 408, 426, 449, 450, 451, 452, 456, 457, 462 and 473 in the amino acid sequence shown in SEQ ID NO: 1, or at a position corresponding to any of these positions.

[0173] Another preferred embodiment of the present invention relates to any of the above variants, which have an amino acid sequence having at least 77% sequence identity with SEQ ID NO: 1, wherein the variant is characterized in that it is selected from the group consisting of 2, 3, 5, 6, 24, 35, 36, 64, 66, 85, 86, 126, 129, 154, 168, 175, 195, 197, 214, 241, 277, 296, 298, 305, 339, 343, 347, 349, 350, 359, 363, 391, 394, 396, 398, 401, 403, 404, 405, 439, 440 444, 445, 446, 447, 448, 453, 454, 455, 458, 459, 460, 461, 479 and 496, or at a position corresponding to any of these positions, has one or more other amino acid residue substitutions, deletions or insertions, and wherein the MDC has improved activity in converting 3-methylcrotonic acid to isobutylene relative to the corresponding MDC from which it is derived.

[0174] Regarding preferred embodiments for substitutions, deletions or insertions of these variants, the above description applies. Thus, in preferred embodiments, the changes made at any of the above positions in these variants are substitutions, deletions and / or insertions as defined above.

[0175] Another preferred embodiment of the present invention relates to 3-methylcrotonate decarboxylase (MDC) variants showing improved activity in converting 3-methylcrotonate to isobutylene relative to the MDC of SEQ ID NO: 1,

[0176] wherein said variant is characterized by:

[0177] It has an amino acid sequence that has at least 74% sequence identity to SEQ ID NO: 1; and

[0178] It shows that one or more amino acid residues are substituted, deleted or inserted by another amino acid residue at positions 25, 74, 80, 166, 196, 198, 204, 208, 236, 237, 238, 366, 368, 390, 395, 402, 406, 408, 426, 449, 450, 451, 452, 456, 457, 462 and 473 in the amino acid sequence shown in SEQ ID NO: 1, or at a position corresponding to any of these positions.

[0179] Another preferred embodiment of the present invention relates to any of the above variants, which have an amino acid sequence having at least 74% sequence identity with SEQ ID NO: 1, wherein the variant is characterized in that it is selected from the group consisting of 2, 3, 5, 6, 24, 35, 36, 64, 66, 85, 86, 126, 129, 154, 168, 175, 195, 197, 214, 240, 241, 277, 296, 298, 302, 305, 339, 343, 347, 349, 350, 359, 363, 391, 394, 396, 398, 401, 403, 404, 405, 407, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 453, 454, 455, 458, 459, 460, 461, 479 and 496, or at a position corresponding to any of these positions, has one or more other amino acid residue substitutions, deletions or insertions, and wherein the MDC has improved activity in converting 3-methylcrotonic acid to isobutylene relative to the corresponding MDC from which it is derived.

[0180] Regarding preferred embodiments for substitutions, deletions or insertions of these variants, the above description applies. Thus, in preferred embodiments, the changes made at any of the above positions in these variants are substitutions, deletions and / or insertions as defined above.

[0181] Another preferred embodiment of the present invention relates to 3-methylcrotonate decarboxylase (MDC) variants showing improved activity in converting 3-methylcrotonate to isobutylene relative to the MDC of SEQ ID NO: 1,

[0182] wherein said variant is characterized by:

[0183] It has an amino acid sequence that has at least 64% sequence identity to SEQ ID NO: 1; and

[0184] It shows that one or more amino acid residues are substituted, deleted or inserted by another amino acid residue at positions 25, 74, 80, 166, 196, 198, 204, 208, 238, 366, 390, 402, 406, 408, 426, 449, 451, 452, 456, 457, 462 and 473 in the amino acid sequence shown in SEQ ID NO: 1, or at a position corresponding to any of these positions.

[0185] Another preferred embodiment of the present invention relates to any of the above variants, which have an amino acid sequence having at least 64% sequence identity with SEQ ID NO: 1, wherein the variant is characterized in that it is selected from the group consisting of 2, 3, 5, 6, 24, 35, 36, 64, 66, 85, 86, 126, 129, 154, 168, 175, 195, 197, 214, 236, 237, 240, 241, 277, 296, 298, 302, 305, 339, 343, 347, 349, 350, 359, 363, 368, 391, 394, 395, 396, 398, 401, 403, 404, 405, 5, 407, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 450, 453, 454, 455, 458, 459, 460, 461, 479 and 496, or at a position corresponding to any of these positions, has one or more other amino acid residue substitutions, deletions or insertions, and wherein the MDC has improved activity in converting 3-methylcrotonic acid to isobutylene relative to the corresponding MDC from which it is derived.

[0186] Regarding preferred embodiments for substitutions, deletions or insertions of these variants, the above description applies. Thus, in preferred embodiments, the changes made at any of the above positions in these variants are substitutions, deletions and / or insertions as defined above.

[0187] Another preferred embodiment of the present invention relates to 3-methylcrotonate decarboxylase (MDC) variants showing improved activity in converting 3-methylcrotonate to isobutylene relative to the MDC of SEQ ID NO: 1,

[0188] wherein said variant is characterized by:

[0189] It has an amino acid sequence that has at least 63% sequence identity to SEQ ID NO: 1; and

[0190] It shows that one or more amino acid residues are substituted, deleted or inserted by another amino acid residue at positions 25, 74, 80, 196, 366, 402, 408, 426, 449, 451, 452, 456, 457 and 473 in the amino acid sequence shown in SEQ ID NO: 1, or at a position corresponding to any of these positions.

[0191] Another preferred embodiment of the present invention relates to any of the above variants, which have an amino acid sequence having at least 63% sequence identity with SEQ ID NO: 1, wherein the variant is characterized in that it is selected from the group consisting of 2, 3, 5, 6, 24, 35, 36, 64, 66, 85, 86, 126, 129, 154, 166, 168, 175, 195, 197, 198, 204, 208, 214, 236, 237, 238, 240, 241, 277, 296, 298, 302, 305, 339, 343, 347, 349, 350, 359, 363, 368, 390, 391, 394, 395, 396, 398, 401, 402, 3, 404, 405, 406, 407, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 450, 453, 454, 455, 458, 459, 460, 461, 462, 479 and 496, or at a position corresponding to any of these positions, has one or more other amino acid residue substitutions, deletions or insertions, and wherein the MDC has improved activity in converting 3-methylcrotonic acid to isobutylene relative to the corresponding MDC from which it is derived.

[0192] Regarding preferred embodiments for substitutions, deletions or insertions of these variants, the above description applies. Thus, in preferred embodiments, the changes made at any of the above positions in these variants are substitutions, deletions and / or insertions as defined above.

[0193] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least one deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur at the position corresponding to SEQ ID NO: 1. Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 453, 459, 460, 461, 479, and 496.

[0194] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at the corresponding positions: A241D, A241N or A241V.

[0195] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least one deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at position 359 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: 1. Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 445, 446, 447, 448, 453, 459, 460, 461, 479, and 496.

[0196] Preferably, the variant has the following substitution in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitution at a position corresponding to said position: A359C.

[0197] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least one deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur at the position corresponding to SEQ ID NO: 1. Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 453, 459, 460, 461, 479, and 496.

[0198] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404F or C404L.

[0199] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least one deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur at the position corresponding to SEQ ID NO: 1. Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0200] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: L448F, L448W or L448Y.

[0201] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least one deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at position 406 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur at the position corresponding to SEQ ID NO: 1. Positions 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 445, 446, 447, 448, 453, 459, 460, 461, 479, and 496.

[0202] Preferably, the variant has the following substitution in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitution at a position corresponding to said position: P406A.

[0203] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least two deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 390 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and the other deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: 1. Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0204] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: R390S-L448W or R390S-L448Y.

[0205] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least two deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and the other deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: 1. Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 453, 459, 460, 461, 479, and 496.

[0206] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404F, A241D-C404L, A241N-C404F or A241N-C404L.

[0207] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising at least two deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and the other deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: 1. Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0208] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-L448F, A241D-L448W, A241D-L448Y, A241N-L448F, A241N-L448W or A241N-L448Y.

[0209] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least two deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and the other deletion / insertion / substitution is located at position 406 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: 1. Positions 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 453, 459, 460, 461, 479, and 496.

[0210] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-P406A or A241N-P406A.

[0211] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least two deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and the other deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: 1. Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 453, 459, 460, 461, 479, and 496.

[0212] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at the corresponding positions: C404L-L448F, C404L-L448W, C404M-L448F, C404M-L448W, C404F-L448F, C404F-L448W, C404F-L448Y or C404L-L448Y.

[0213] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least two deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and the other deletion / insertion / substitution is located at position 406 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: 1. Positions 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 453, 459, 460, 461, 479, and 496.

[0214] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404L-P406A or C404F-P406A.

[0215] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least two deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 406 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and the other deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: 1. Positions 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0216] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: P406A-L448F, P406A-L448W or P406A-L448Y.

[0217] In a preferred embodiment, the MDC variant of the invention showing improved activity in the conversion of 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0218] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to the positions: A241D-C404F-L448F, A241D-C404F-L448Y, A241D-C404L-L448F, A241D-C404L-L448W, A241D-C404L-L448Y, A241N-C404F-L448 F, A241N-C404F-L448W, A241N-C404F-L448Y, A241N-C404L-L448F, A241N-C404L-L448W, A241N-C404L-L448Y, A241D-C404F-L448W, A241N-C404M-L448W, or A241D-C404M-L448W.

[0219] In a preferred embodiment, the MDC variant of the invention showing improved activity in the conversion of 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 406 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 453, 459, 460, 461, 479, and 496.

[0220] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-C404F-P406A, A241D-C404L-P406A, A241N-C404L-P406A or A241N-C404F-P406A.

[0221] In a preferred embodiment, the MDC variant of the invention showing improved activity in the conversion of 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 406 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0222] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-P406A-L448F, A241D-P406A-L448Y, A241N-P406A-L448F, A241N-P406A-L448W, A241N-P406A-L448Y or A241D-P406A-L448W.

[0223] In a preferred embodiment, the MDC variant of the invention showing improved activity in the conversion of 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 406 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0224] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: C404F-P406A-L448F, C404F-P406A-L448W, C404F-P406A-L448Y, C404L-P406A-L448F, C404L-P406A-L448Y, C404M-P406A-L448W, C404M-P406S-L448W or C404L-P406A-L448W.

[0225] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 446 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 447, 453, 459, 460, 461, 479, and 496.

[0226] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: C404F-L446I-L448W.

[0227] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 446 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 447, 453, 459, 460, 461, 479, and 496.

[0228] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: C404M-L446N-L448W or C404M-L446I-L448W.

[0229] In a preferred embodiment, the MDC variant of the invention showing improved activity in the conversion of 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 240 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to that position, another deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to that position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to that position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0230] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: V240I-C404M-L448F.

[0231] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 404 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 450 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 241, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0232] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: C404M-L448W-T450A or C404M-L448W-T450H.

[0233] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 401 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0234] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-F401Y-L448W or A241N-F401Y-L448W.

[0235] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 444 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0236] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-P444E-L448W.

[0237] In a preferred embodiment, the MDC variant of the invention showing improved activity in the conversion of 3-methylcrotonic acid to isobutylene is characterized in that it comprises at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 403 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 404, 405, 439, 440, 441, 442, 443, 444, 445, 446, 447, 453, 459, 460, 461, 479, and 496.

[0238] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-S403G-L448W, A241N-S403P-L448W, A241D-S403P-L448W or A241N-S403G-L448W.

[0239] In a preferred embodiment, the MDC variant of the invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising at least three deletions, substitutions and / or insertions, wherein one deletion / insertion / substitution is located at position 241 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, another deletion / insertion / substitution is located at position 446 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position, and another deletion / insertion / substitution is located at position 448 of the amino acid sequence shown in SEQ ID NO: 1 or at a position corresponding to this position. Preferably, this variant also has one or more substitutions, deletions and / or insertions compared to the corresponding sequence from which it is derived, and wherein these substitutions, deletions and / or insertions occur in the amino acid sequence corresponding to SEQ ID NO: Positions 406, 25, 35, 36, 74, 80, 86, 126, 129, 166, 196, 198, 204, 208, 236, 237, 238, 240, 298, 302, 359, 366, 368, 390, 395, 396, 402, 407, 408, 426, 449, 450, 451, 452, 454, 455, 456, 457, 458, 462, 473, 2, 3, 5, 6, 24, 64, 66, 85, 154, 168, 175, 195, 197, 214, 277, 296, 305, 339, 343, 347, 349, 350, 363, 391, 394, 398, 401, 403, 404, 405, 439, 440, 441, 442, 443, 444, 445, 447, 453, 459, 460, 461, 479, and 496.

[0240] Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241N-L446V-L448W.

[0241] In other preferred embodiments, the MDC variants of the present invention that show improved activity in converting 3-methylcrotonic acid to isobutylene are characterized by comprising multiple mutations. As further illustrated in the examples below, variants with multiple mutations have been found that exhibit an increased reaction rate for converting 3-methylcrotonic acid to isobutylene. These variants with multiple mutations are summarized as follows:

[0242] Therefore, in a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-C404F-P406A-L448F, A241D-C404F-P406A-L448Y, A241D-C404L-P406A-L448F, A241D-C404L-P406A-L448Y, A241N-C404F-P406A-L448F, A241N-C404F-P406A-L448Y, A241N-C404L-P406A-L448F or A241N-C404L-P406A-L448Y.

[0243] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404M-P406A-L446I-L448W or C404M-P406S-L446I-L448W.

[0244] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403R-C404M-L446I-L448W.

[0245] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: C404M-L446I-L448W-T450A, C404M-L446I-L448W-T450H, C404M-L446I-L448W-T450M, C404M-L446I-L448W-T450N, C404M-L446I-L448W-T450S, C404M-L446N-L448W-T450A or C404M-L446N-L448W-T450H.

[0246] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404M-P406A-L446N-L448W, C404M-P406S-L446N-L448W.

[0247] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions:

[0248] C404M-P406A-L446I-L448W-T450A, C404M-P406S-L446I-L448W-T450A, C404M-P406S-L446I-L448W-T450H, C404M-P406A-L446N-L448W-T450A, C404M-P406A-L446N-L448W-T450H, C404M-P406S-L446N-L448W-T450A, C404M-P406S-L446N-L448W-T450H, C404M-P406A-L446I-L448W-T450H.

[0249] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404F-L446I-L448W.

[0250] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404F-P406A-L448W, A241D-C404F-P406S-L448W or A241D-C404L-P406A-L448W.

[0251] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406, 443 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404L-P406A-G443D-L448W.

[0252] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404L-P406A-L446V-L448W.

[0253] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404L-P406A-L446V-L448W-T450M.

[0254] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404L-P406A-L448W-T450M.

[0255] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404M-P406A-L448W.

[0256] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 401, 404, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-F401Y-C404F-L446I-L448W.

[0257] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 401, 404 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-F401Y-C404F-L448W or A241D-F401Y-C404M-L448W.

[0258] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 401, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-F401Y-C404F-P406A-L448W, A241D-F401Y-C404M-P406A-L448W.

[0259] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 401, 403, 404, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-F401Y-S403G-C404F-L446I-L448W.

[0260] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 401, 403, 404 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-F401Y-S403G-C404F-L448W or A241D-F401Y-S403G-C404M-L448W.

[0261] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 401, 403, 404, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-F401Y-S403P-C404F-L446I-L448W.

[0262] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 401, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-F401Y-S403P-C404M-P406A-L448W.

[0263] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 401, 403, 404 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-F401Y-S403P-C404F-L448W.

[0264] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-C404L-P406A-L446V-L448W.

[0265] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-C404L-P406A-L446V-L448W-T450M.

[0266] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-C404L-P406A-L448W.

[0267] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-C404L-P406A-L448W-T450M.

[0268] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 403, 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-S403C-C404L-P406A-L446V-L448W.

[0269] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 403, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-S403C-C404L-P406A-L446V-L448W-T450M or A241D-G402A-S403V-C404L-P406A-L446V-L448W-T450M.

[0270] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-S403C-C404L-P406A-L448W or A241D-G402A-S403V-C404L-P406A-L448W.

[0271] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 403, 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-S403C-C404L-P406A-L448W-T450M or A241D-G402A-S403V-C404L-P406A-L448W-T450M.

[0272] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 403, 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-S403V-C404L-P406A-L446V-L448W.

[0273] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-L446V-L448W.

[0274] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-L446V-L448W-T450M.

[0275] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-L448W, A241D-S403G-C404F-P406A-L448W or A241D-S403G-C404M-P406A-L448W.

[0276] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403P-C404F-L446I-L448W.

[0277] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-L448W-T450M.

[0278] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403G-C404F-L446I-L448W.

[0279] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403G-C404F-L448W, A241D-S403P-C404F-L448W or A241D-S403P-C404M-L448W.

[0280] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403P-C404F-P406A-L448W, A241D-S403P-C404M-P406A-L448W or A241D-S403V-C404L-P406A-L448W.

[0281] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403V-C404L-P406A-L446V-L448W.

[0282] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403V-C404L-P406A-L446V-L448W-T450M.

[0283] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403V-C404L-P406A-L448W-T450M.

[0284] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 405, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241N-C404F-L405H-P406A-L448W.

[0285] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241N-C404F-P406A-L448W.

[0286] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241N-C404L-P406A-L446C-L448W or A241N-C404L-P406A-L446V-L448W.

[0287] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241N-C404L-P406A-L448W or A241N-C404M-P406A-L448W.

[0288] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241N-C404L-P406A-L448W-L449I.

[0289] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241N-C404L-P406A-L448W-T450M or A241N-C404L-P406A-L448W-T450Q.

[0290] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241N-S403C-C404L-P406A-L448W, A241N-S403N-C404L-P406A-L448W or A241N-S403V-C404L-P406A-L448W.

[0291] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404L-P406A-L446F-L448W, C404L-P406A-L446S-L448W or C404L-P406A-L446V-L448W.

[0292] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404L-P406A-L448W-T450M, C404M-P406A-L448W-T450A, C404M-P406S-L448W-T450A, C404M-P406A-L448W-T450H or C404M-P406S-L448W-T450H.

[0293] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 406, 444 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404L-P406A-P444H-L448W.

[0294] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 85, 241, 404, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: P85L-A241N-C404M-L448W-T450M.

[0295] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403V-C404L-P406A-L448W.

[0296] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-L448W, A241D-S403C-C404L-P406A-G443H-L448W or A241D-S403C-C404L-P406A-G443N-L448W.

[0297] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-L448W-L449I.

[0298] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 444 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-P444A-L448W, A241D-S403C-C404L-P406A-P444H-L448W or A241D-S403C-C404L-P406A-P444L-L448W.

[0299] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 403, 404, 406, 443 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-S403C-C404L-P406A-G443H-L448W, A241D-G402A-S403C-C404L-P406A-G443S-L448W.

[0300] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 403, 404, 406, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-S403C-C404L-P406A-L446M-L448W.

[0301] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 402, 403, 404, 406, 444 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-G402A-S403C-C404L-P406A-P444F-L448W or A241D-G402A-S403C-C404L-P406A-P444H-L448W.

[0302] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403H-C404L-P406A-L448W-T450M.

[0303] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, such a variant comprises a deletion, substitution and / or insertion at positions 241, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1. The amino acid sequence shown in NO: 1 has the following substitutions, or has the following substitutions at positions corresponding to the positions: A241D-S403C-C404L-P406A-G443A-L448W-T450M, A241D-S403C-C404L-P406A-G443F-L448W-T450M, A241D-S403C-C404L-P406A-G443Y-L448W-T450M, A241D-S403V-C404L-P406 A-G443A-L448W-T450M, A241D-S403V-C404L-P406A-G443D-L448W-T450M, A241D-S403V-C404L-P406A-G443F-L4 48W-T450M, A241D-S403V-C404L-P406A-G443N-L448W-T450M or A241D-S403V-C404L-P406A-G443S-L448W-T450M.

[0304] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 444, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-P444A-L448W-T450M, A241D-S403C-C404L-P406A-P444F-L448W-T450M and A241D-S403C-C404L-P406A-P444T-L448W-T450M.

[0305] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403V-C404L-P406A-G443D-L446V-L448W.

[0306] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403V-C404L-P406A-G443D-L448W.

[0307] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 445, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403V-C404L-P406A-V445L-L448W-T450M.

[0308] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404L-P406A-G443F-L446V-L448W-T450M.

[0309] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404L-P406A-L446V-L448W-T450A.

[0310] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, such a variant comprises a deletion, substitution and / or insertion at positions 241, 403, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1. The amino acid sequence shown in NO: 1 has the following substitutions, or has the following substitutions at positions corresponding to the positions: A241D-S403C-C404L-P406A-G443A-L446V-L448W-T450M, A241D-S403C-C404L-P406A-G443S-L446V-L448W-T450M, A241D-S403C-C404L-P406A-G443W-L446V-L448W-T450M, A241 D-S403C-C404L-P406A-G443Y-L446V-L448W-T450M, A241D-S403V-C404L-P406A-G443D-L446V-L448W-T450M, A2 41D-S403V-C404L-P406A-G443F-L446V-L448W-T450M or A241D-S403V-C404L-P406A-G443Y-L446V-L448W-T450M.

[0311] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 198, 241, 403, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: H198Q-A241D-S403C-C404L-P406A-G443F-L446V-L448W-T450M.

[0312] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-P444H-L446V-L448W-T450M.

[0313] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408I-L446V-L448W-T450M.

[0314] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-L446M-L448W-T450M, A241D-S403V-C404L-P406A-L446V-L448W-T450H, A241D-S403A-C404L-P406 A-L446V-L448W-T450M, A241D-S403V-C404L-P406A-L446V-L448W-T450M, A241D-S403V-C404L-P406A-L446A-L448W-T450M, or A241D-S403V-C404L-P406A-L446M-L448W-T450M.

[0315] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403V-C404L-P406A-V408I-L446V-L448W-T450M.

[0316] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404M-P406A-G443W-L446I-L448W-T450H, C404M-P406A-G443Y-L446I-L448W-T450H.

[0317] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 405, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404M-L405I-P406A-L446I-L448W-T450H.

[0318] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-C404M-P406A-L446I-L448W-T450H.

[0319] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 406, 407, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404M-P406A-Q407K-L446I-L448W-T450H.

[0320] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-L446I-L448W-T450H or S403P-C404M-P406A-L446I-L448W-T450H.

[0321] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 405, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404M-L405I-P406A-L448W-T450H.

[0322] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 405, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-L405I-P406A-G443Y-L448W-T450H.

[0323] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-L448W-T450H.

[0324] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 405, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-L405I-P406A-L448W-T450H.

[0325] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 404, 405, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-C404M-L405I-P406A-L446I-L448W-T450H.

[0326] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 404, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-C404M-P406A-L448W-T450H.

[0327] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 405, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-L405I-P406A-L448W-T450H.

[0328] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 405, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404M-L405I-P406A-G443Y-L446I-L448W-T450H.

[0329] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 404, 405, 406, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-C404M-L405I-P406A-L448W-T450H.

[0330] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-L446I-L448W-T450H.

[0331] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 405, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-L405I-P406A-G443Y-L448W-T450H.

[0332] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404M-P406A-G443Y-L448W-T450H.

[0333] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-G443Y-L446I-L448W-T450H.

[0334] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-G443Y-L448W-T450H.

[0335] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 405, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-L405I-P406A-L446I-L448W-T450H.

[0336] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 404, 405, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-C404M-L405I-P406A-G443Y-L446I-L448W-T450H.

[0337] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 405, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-L405I-P406A-G443Y-L446I-L448W-T450H.

[0338] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 404, 405, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: C404M-L405I-P406A-G443Y-L448W-T450H.

[0339] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 405, 406, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-L405I-P406A-L446I-L448W-T450H.

[0340] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-C404M-P406A-G443Y-L446I-L448W-T450H.

[0341] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 405, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-L405I-P406A-G443Y-L446I-L448W-T450H.

[0342] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-G443Y-L446I-L448W-T450H.

[0343] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-L448W-L449I.

[0344] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-P444H-L446M-L448W-T450M.

[0345] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0346] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-P444A-L448W.

[0347] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443Y-P444H-L446M-L448W-T450M.

[0348] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M.

[0349] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443Y-L446M-L448W-T450M.

[0350] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 25, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A25E-A241D-S403C-C404L-P406A-L448W.

[0351] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-A241D-S403C-C404L-P406A-L448W.

[0352] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 80, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A80S-A241D-S403C-C404L-P406A-L448W.

[0353] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 24, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: E24A-A241D-S403C-C404L-P406A-L448W, E24D-A241D-S403C-C404L-P406A-L448W, E24L-A241D-S403C-C404L-P406A-L448W or E24V-A241D-S403C-C404L-P406A-L448W.

[0354] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 237, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: G237D-A241D-S403C-C404L-P406A-L448W or G237P-A241D-S403C-C404L-P406A-L448W.

[0355] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443A-L448W.

[0356] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 236, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: I236L-A241D-S403C-C404L-P406A-L448W or I236V-A241D-S403C-C404L-P406A-L448W.

[0357] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 296, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-I296Q-S403C-C404L-P406A-L448W.

[0358] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-A241D-S403C-C404L-P406A-L448W.

[0359] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 64, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: N64H-A241D-S403C-C404L-P406A-L448W.

[0360] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-L448W-P479C or A241D-S403C-C404L-P406A-L448W-P479I or A241D-S403C-C404L-P406A-L448W-P479 L or A241D-S403C-C404L-P406A-L448W-P479M or A241D-S403C-C404L-P406A-L448W-P479S or A241D-S403C-C404L-P406A-L448W-P479T or A241D-S403C-C404L-P406A-L448W-P479V.

[0361] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 448 and 496 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-L448W-R496L.

[0362] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 175, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S175E-A241D-S403C-C404L-P406A-L448W.

[0363] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 448 and 473 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-L448W-A473S.

[0364] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 86, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S86N-A241D-S403C-C404L-P406A-L448W or S86Y-A241D-S403C-C404L-P406A-L448W.

[0365] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 240, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: V240N-A241D-S403C-C404L-P406A-L448W.

[0366] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 240, 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: V240N-A241D-S403C-C404L-P406A-L448W-P479V.

[0367] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 214, 237, 241, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-K214T-G237P-A241D-S403C-C404L-P406A-L448W.

[0368] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 237, 241, 296, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-G237P-A241D-I296Q-S403C-C404L-P406A-L448W.

[0369] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 237, 241, 296, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-G237P-A241D-I296Q-S403C-C404L-P406A-L448W-P479V.

[0370] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 241, 403, 404, 406, 448 and 496 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-A241D-S403C-C404L-P406A-L448W-R496L.

[0371] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 240, 241, 403, 404, 406, 448 and 496 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: V240N-A241D-S403C-C404L-P406A-L448W-R496L.

[0372] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 237, 240, 241, 296, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-G237P-V240N-A241D-I296Q-S403C-C404L-P406A-L448W.

[0373] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-A241D-S403C-C404L-P406A-L448W-P479V.

[0374] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 214, 237, 240, 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-K214T-G237P-V240N-A241D-S403C-C404L-P406A-L448W-P479V.

[0375] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 214, 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-K214T-A241D-S403C-C404L-P406A-L448W-P479V.

[0376] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 237, 241, 296, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: G237P-A241D-I296Q-S403C-C404L-P406A-L448W-P479V.

[0377] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 214, 237, 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-K214T-G237P-A241D-S403C-C404L-P406A-L448W-P479V.

[0378] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 296, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-I296Q-S403C-C404L-P406A-L448W-P479V.

[0379] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 214, 241, 296, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-K214T-A241D-I296Q-S403C-C404L-P406A-L448W.

[0380] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 241, 403, 404, 406, 443 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-A241D-S403C-C404L-P406A-G443N-L448W.

[0381] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 241, 296, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-A241D-I296Q-S403C-C404L-P406A-L448W.

[0382] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 241, 296, 403, 404, 406 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-A241D-I296Q-S403C-C404L-P406A-L448W.

[0383] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 237, 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: G237P-A241D-S403C-C404L-P406A-L448W-P479V.

[0384] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 214, 241, 296, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-K214T-A241D-I296Q-S403C-C404L-P406A-L448W-P479V.

[0385] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 237, 240, 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-G237P-V240N-A241D-S403C-C404L-P406A-L448W-P479V.

[0386] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 237, 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-G237P-A241D-S403C-C404L-P406A-L448W-P479V.

[0387] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 241, 296, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-A241D-I296Q-S403C-C404L-P406A-L448W-P479V.

[0388] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 66, 241, 296, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A66H-A241D-I296Q-S403C-C404L-P406A-L448W-P479V.

[0389] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 241, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-A241D-S403C-C404L-P406A-G443F-L448W-T450M.

[0390] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 214, 237, 241, 403, 404, 406, 448 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: K214T-G237P-A241D-S403C-C404L-P406A-L448W-P479V.

[0391] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M.

[0392] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408C-G443F-L448W-T450M or A241D-S403C-C404L-P406A-V408L-G443F-L448W-T450M.

[0393] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 445, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443F-V445L-L448W-T450M or A241D-S403C-C404L-P406A-G443F-V445S-L448W-T450M or A241D-S403C-C404L-P406A-G443F-V445T-L448W-T450M.

[0394] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 445 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-V445T-L448W.

[0395] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-P444A-L448W.

[0396] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 405, 406, 443, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-L405I-P406A-G443D-L448W-L449I.

[0397] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-L448W-L449I.

[0398] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 445, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-V445L-L448W-L449I.

[0399] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443A-P444H-L448W-L449I or A241D-S403C-C404L-P406A-G443F-P444H-L448W-L449I or A241D-S403C-C404L-P406A-G443L-P444H-L448W-L449I or A241D-S403C-C404L-P406A-G443S-P444H-L448W-L449I.

[0400] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-P444H-L448W.

[0401] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V.

[0402] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0403] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 404, 405, 406, 443, 446, 448, 449 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-C404L-L405M-P406A-G443F-L446V-L448W-L449M-T450M.

[0404] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403Q-C404L-P406A-G443F-L446V-L448W-T450M.

[0405] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 444, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P444H-L448W-T450M.

[0406] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 444, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406S-P444H-L448W-T450M.

[0407] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 195, 241, 403, 404, 406, 444, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: L195I-A241D-S403C-C404L-P406A-P444H-L448W-T450M.

[0408] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 444, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-P444H-L448W-T450M.

[0409] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 407, 444, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-Q407R-P444H-L448W-T450M or A241D-S403C-C404L-P406A-Q407S-P444H-L448W-T450M.

[0410] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 444, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408I-P444H-L448W-T450M.

[0411] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 195, 241, 403, 404, 406, 408, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: L195I-A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M.

[0412] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 408, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M.

[0413] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 444, 445, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408I-P444H-V445C-L446M-L448W-T450M.

[0414] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443Y-P444H-L446M-L448W-T450M.

[0415] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V or M197V-A241D-S403C-C404L-P406A-G443S-P444H-L448W-L449I.

[0416] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0417] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 443, 446, 448, 450 and 455 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-G443Y-L446I-L448W-T450H-Q455H.

[0418] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: S403A-C404M-P406A-G443Y-L446I-L448W-T450H or S403I-C404M-P406A-G443Y-L446I-L448W-T450H or S403Q-C404M-P406A-G443Y-L446I-L448W-T450H or S403V-C404M-P406A-G443Y-L446I-L448W-T450H or S403C-C404M-P406G-G443Y-L446I-L448W-T450H.

[0419] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 442, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: S403C-C404M-P406A-D442A-G443Y-L446I-L448W-T450H or S403C-C404M-P406A-D442E-G443Y-L446I-L448W-T450H or S403C-C404M-P406A-D442G-G443Y-L446I-L448W-T450H or S403C-C404M-P406A-D442S-G443Y-L446I-L448W-T450H.

[0420] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 443, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-G443Y-P444H-L446I-L448W-T450H.

[0421] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 443, 445, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: S403C-C404M-P406A-G443Y-V445A-L446I-L448W-T450H or S403C-C404M-P406A-G443Y-V445C-L446I-L448W-T450H or S403C-C404M-P406A-G443Y-V445L-L446I-L448W-T450H.

[0422] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 443, 446, 448, 450 and 451 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-G443Y-L446I-L448W-T450H-C451N or S403C-C404M-P406A-G443Y-L446I-L448W-T450H-C451S.

[0423] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 196, 197, 403, 404, 406, 443, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: V196I-M197V-S403C-C404M-P406A-G443Y-L446I-L448W.

[0424] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 443, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406G-G443Y-L446I-L448W or M197V-S403C-C404M-P406S-G443Y-L446I-L448W.

[0425] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 442, 443, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: M197V-S403C-C404M-P406A-D442A-G443Y-L446I-L448W or M197V-S403C-C404M-P406A-D442C-G443Y-L446I-L448W or M197V-S403C-C404M-P406A-D442G-G443Y-L446I-L448W or M197V-S403C-C404M-P406A-D442H-G443Y-L446I-L448W.

[0426] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 442, 443, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-D442H-G443Y-L446I-L448W.

[0427] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 442, 443, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-D442N-G443Y-L446I-L448W or M197V-S403C-C404M-P406A-D442S-G443Y-L446I-L448W.

[0428] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 443, 445, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-G443Y-V445S-L446I-L448W or M197V-S403C-C404M-P406A-G443Y-V445T-L446I-L448W.

[0429] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 442, 443, 445, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-D442A-G443Y-V445L-L446I-L448W-T450H.

[0430] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 442, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: M197V-S403C-C404M-P406A-D442A-G443Y-L446I-L448W-T450H or M197V-S403C-C404M-P406A-D442Q-G443Y-L446I-L448W-T450H or M197V-S403C-C404M-P406A-D442N-G443Y-L446I-L448W-T450H or M197V-S403C-C404M-P406A-D442S-G443Y-L446I-L448W-T450H.

[0431] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 441, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-E441R-G443D-P444H-L448W-L449I.

[0432] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 442, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, such a variant comprises a deletion, substitution and / or insertion at positions 241, 403, 404, 406, 442, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1. The amino acid sequence shown in NO: 1 has the following substitutions, or has the following substitutions at the positions corresponding to the positions: A241D-S403C-C404L-P406A-D442L-G443D-P444H-L448W-L449I or A241D-S403C-C404L-P406A-D442R-G443D-P444H-L448W-L449I or A241D-S403C-C404L-P406A-D442M-G443D D-P444H-L448W-L449I or A241D-S403C-C404L-P406A-D442A-G443D-P444H-L448W-L449I or A241D-S403C-C404L-P406A-D442S-G443D-P444H-L448W-L449I or A241D-S403C-C404L-P406A-D442G-G443D-P444H-L448W-L449I.

[0433] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444, 445, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-P444H-V445T-L448W-L449I.

[0434] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 407, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-Q407C-G443D-P444H-L448W-L449I.

[0435] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444, 448, 449 and 454 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454A or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454W or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454W -C404L-P406A-G443D-P444H-L448W-L449I-P454V or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454M or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454H or A241D-S 403C-C404L-P406A-G443D-P444H-L448W-L449I-P454T or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454G or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454K or A24 1D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454Q or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454L.

[0436] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444, 448, 449 and 459 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A459Y or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A459N.

[0437] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444, 448, 449 and 460 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A460N or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A460L or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A460M or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A460R.

[0438] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 444, 448, 449 and 461 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-R461V or A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-R461S.

[0439] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 154, 241, 339, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: E154D-A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0440] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 302, 339, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-L302R-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0441] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 363, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-A363G-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0442] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 390, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-R390D-S403C-C404L-P406A-G443D-P444H-L448W-L449I or A241D-E339H-R390L-S403C-C404L-P406A-G443D-P444H-L448W-L449I D-P444H-L448W-L449I or A241D-E339H-R390N-S403C-C404L-P406A-G443D-P444H-L448W-L449I or A241D-E339H-R390Q-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0443] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 391, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-E339H-R391D-S403C-C404L-P406A-G443D-P444H-L448W-L449I or A241D-E339H-R391W-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0444] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 394, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-E394Q-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0445] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at position 3, 241, 339, 394, 403, 404, 406, 443, 444, 448 or 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: V3M-A241D-E339H-E394T-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0446] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 398, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-G398R-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0447] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 129, 241, 339, 398, 403, 404, 406, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A129V-A241D-E339H-G398C-S403C-C404L-P406A-G443D-P444H-L448W-L449I.

[0448] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 408, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-E339H-S403C-C404L-P406A-V408L-G443D-P444H-L448W-L449I or A241D-E339H-S403C-C404L-P406A-V408M-G443D-P444H-L448W-L449I.

[0449] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 441, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-S403C-C404L-P406A-E441S-G443D-P444H-L448W-L449I.

[0450] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 442, 443, 444, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-E339H-S403C-C404L-P406A-D442H-G443D-P444H-L448W-L449I or A241D-E339H-S403C-C404L-P406A-D442R-G443D-P444H-L448W-L449I.

[0451] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 168, 241, 339, 403, 404, 406, 443, 444, 445, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: I168V-A241D-E339H-S403C-C404L-P406A-G443D-P444H-V445L-L448W-L449I.

[0452] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 443, 444, 446, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-S403C-C404L-P406A-G443D-P444H-L446M-L448W-L449I.

[0453] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 443, 444, 448, 449 and 452 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-Y452F.

[0454] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 443, 444, 448, 449 and 453 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-T453L.

[0455] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 443, 444, 448, 449 and 454 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, such a variant comprises a deletion, substitution and / or insertion at positions 241, 339, 403, 404, 406, 443, 444, 448, 449 and 454 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. The amino acid sequence shown in NO: 1 has the following substitutions, or has the following substitutions at the positions corresponding to the positions: A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454H or A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454K or A241D-E339H-S403C-C404L-P406A-G443D-P444 H-L448W-L449I-P454R or A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454S or A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454T or A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454W.

[0456] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 443, 444, 448, 449, 461 and 479 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-R461V-P479S.

[0457] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 407, 443 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-Q407A-G443N-L448W.

[0458] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 442, 443 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-D442A-G443N-L448W.

[0459] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443N-L448W-T450H.

[0460] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448 and 453 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443N-L448W-T453R.

[0461] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 446 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443N-L446M-L448W.

[0462] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 339, 403, 404, 406, 441, 443 444, 446, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-E339H-S403C-C404L-P406A-E441K-G443D-P444H-L446M-L448W-L449I.

[0463] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 237, 241, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: M197V-G237A-A241D-S403C-C404L-P406A-G443F-L448W-T450M or M197V-G237D-A241D-S403C-C404L-P406A-G443F-L448W-T450M or M197V-G237N-A241D-S403C-C404L-P406A-G443F-L448W-T450M or M197V-G237P-A241D-S403C-C404L-P406A-G443F-L448W-T450M.

[0464] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 238, 241, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: M197V-D238H-A241D-S403C-C404L-P406A-G443F-L448W-T450M or M197V-D238R-A241D-S403C-C404L-P406A-G443F-L448W-T450M or M197V-D238S-A241D-S403C-C404L-P406A-G443F-L448W-T450M or M197V-D238W-A241D-S403C-C404L-P406A-G443F-L448W-T450M.

[0465] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 302, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: M197V-A241D-L302A-S403C-C404L-P406A-G443F-L448W-T450M or M197V-A241D-L302K-S403C-C404L-P406A-G443F-L448W-T450M or M197V-A241D-L302M-S403C-C404L-P406A-G443F-L448W-T450M or M197V-A241D-L302R-S403C-C404L-P406A-G443F-L448W-T450M.

[0466] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 359, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-A359V-S403C-C404L-P406A-G443F-L448W-T450M.

[0467] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 398, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-G398R-S403C-C404L-P406A-G443F-L448W-T450M.

[0468] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 394, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-E394C-S403C-C404L-P406A-G443F-L448W-T450M or M197V-A241D-E394D-S403C-C404L-P406A-G443F-L448W-T450M.

[0469] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 396, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-V396I-S403C-C404L-P406A-G443F-L448W-T450M.

[0470] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 35, 197, 241, 403, 404, 406, 407, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: V35I-M197V-A241D-S403C-C404L-P406A-Q407I-G443F-L448W-T450M.

[0471] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 408, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-V408A-G443F-L448W-T450M.

[0472] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 2, 197, 241, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: Y2N-M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M.

[0473] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 439, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-R439C-G443F-L448W-T450M.

[0474] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 440, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-F440L-G443F-L448W-T450M.

[0475] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 448, 450 and 460 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-A460F or M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-A460L or M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-A460R.

[0476] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 448, 450 and 454 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-P454T.

[0477] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 448, 450 and 462 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-A462V.

[0478] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406G-Q407T-G443Y-L446I-L448W-T450H.

[0479] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 5, 197, 403, 404, 406, 442, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M5I-M197V-S403C-C404M-P406G-D442N-G443Y-L446I-L448W-T450H.

[0480] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444, 448, 449 and 459 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-A459D.

[0481] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 449 and 459 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-L448W-L449I-A459G.

[0482] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 446, 448, 450 and 459 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H-A459G.

[0483] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 443, 446, 448, 450 and 459 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-G443Y-L446I-L448W-T450H-A459G.

[0484] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 449 and 459 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-L448W-L449I-A459R.

[0485] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 450 and 460 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443Y-L448W-T450M-A460E.

[0486] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 444, 446, 448, 450 and 460 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-A460G.

[0487] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444, 448, 449, 460 and 462 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-A460G-A462V.

[0488] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 450 and 460 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443Y-L448W-T450M-A460L.

[0489] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 446, 448, 450 and 460 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H-A460L.

[0490] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 444, 446, 448, 450 and 460 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-A460Q.

[0491] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 450 and 462 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443Y-L448W-T450M-A462C.

[0492] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 442, 443, 446, 448, 450 and 462 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-D442N-G443Y-L446I-L448W-T450H-A462C.

[0493] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 450 and 462 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443Y-L448W-T450M-A462V.

[0494] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 446, 448, 450 and 462 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H-A462V.

[0495] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 446, 448, 450, 454 and 462 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H-P454Q-A462V.

[0496] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 198, 403, 404, 406, 407, 443, 446, 448, and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: H198W-S403V-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H.

[0497] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 74, 198, 403, 404, 406, 407, 443, 446, 448, and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: L74V-H198W-S403V-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H.

[0498] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 198, 403, 404, 406, 442, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: H198W-S403C-C404M-P406A-D442Q-G443Y-L446I-L448W-T450H.

[0499] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 441, 443, 448 and 449 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-E441G-G443D-L448W-L449I.

[0500] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 208, 241, 403, 404, 406, 408, 443, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: Q208L-A241D-S403C-C404L-P406A-V408I-G443R-P444H-L446M-L448W-T450M.

[0501] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 443, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408I-G443W-P444H-L446M-L448W-T450M.

[0502] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 449 and 458 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-L448W-L449I-H458G.

[0503] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 195, 403, 404, 406, 407, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: L195V-S403C-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H.

[0504] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 195, 403, 404, 406, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: L195V-S403C-C404M-P406A-G443Y-L446I-L448W-T450H.

[0505] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443Y-L448W-T450M.

[0506] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 407, 443, 446, 448, and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H.

[0507] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 442, 443, 446, 448, 450 and 456 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-D442N-G443Y-L446I-L448W-T450H-E456Q.

[0508] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404F-P406A-Q407T-G443Y-L446I-L448W-T450H.

[0509] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 444, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-Q407T-G443Y-P444F-L446I-L448W-T450H.

[0510] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 449 and 454 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-L448W-L449I-P454K.

[0511] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444, 448, 449 and 454 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-P454K.

[0512] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 449 and 454 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-L448W-L449I-P454R.

[0513] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444, 448, 449 and 454 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-P454R.

[0514] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 449 and 455 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-L448W-L449I-Q455S.

[0515] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 442, 443, 446, 448, 450 and 455 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-D442N-G443Y-L446I-L448W-T450H-Q455V.

[0516] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 446, 448, 450 and 457 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H-R457K.

[0517] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 403, 404, 406, 442, 443, 446, 448, 450, and 461 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-S403C-C404M-P406A-D442N-G443Y-L446I-L448W-T450H-R461G.

[0518] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 444, 446, 448, 450, and 461 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-R461S.

[0519] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444, 448, 449 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-T450H.

[0520] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 443, 448, 449 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: A241D-S403C-C404L-P406A-G443D-L448W-L449I-T450V.

[0521] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444, 448, 449 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-T450V.

[0522] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 36, 197, 403, 404, 406, 442, 443, 446, 448, 450 and 453 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: H36Y-M197V-S403C-C404M-P406A-D442N-G443Y-L446I-L448W-T450H-T453G.

[0523] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 446, 448, 450 and 453 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H-T453N.

[0524] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 198, 403, 404, 406, 443, 446, 448, 450 and 453 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: H198W-S403C-C404M-P406A-G443Y-L446I-L448W-T450H-T453P.

[0525] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 241, 403, 404, 406, 408, 444, 446, 448, 450 and 453 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, the variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or has the following substitutions at positions corresponding to said positions: A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-T453R or A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-T453S.

[0526] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 403, 404, 406, 407, 443, 445, 446, 448 and 450 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has the following substitutions in the amino acid sequence shown in SEQ ID NO: 1, or at positions corresponding to said positions: S403C-C404M-P406A-Q407T-G443Y-V445L-L446I-L448W-T450H or S403C-C404M-P406A-Q407T-G443Y-V445S-L446I-L448W-T450H.

[0527] In a preferred embodiment, the MDC variant of the present invention showing improved activity in converting 3-methylcrotonic acid to isobutylene is characterized by comprising a deletion, substitution and / or insertion, wherein the deletion / insertion / substitution is located at positions 197, 241, 403, 404, 406, 443, 444 and 448 of the amino acid sequence shown in SEQ ID NO: 1 or at positions corresponding to these positions. Preferably, this variant has ...

Claims

1. A variant of 3-methylcrotonate decarboxylase, which exhibits improved activity relative to the MDC of SEQ ID NO: 1 in converting 3-methylcrotonate to isobutylene, wherein the variant is a combination of mutations at the amino acid residue positions of the amino acid sequence of SEQ ID NO: 1 selected from the following: -A241D-C404F; -A241D-C404F-L448F; -A241D-C404F-L448Y; -A241D-C404F-P406A; -A241D-C404F-P406A-L448F; -A241D-C404F-P406A-L448Y; -A241D-C404L; -A241D-C404L-L448F; -A241D-C404L-L448W; -A241D-C404L-L448Y; -A241D-C404L-P406A; -A241D-C404L-P406A-L448F; -A241D-C404L-P406A-L448Y; -A241N-C404F; -A241N-C404F-L448F; -A241N-C404F-L448W; -A241N-C404F-L448Y; -A241N-C404F-P406A; -A241N-C404F-P406A-L448F; -A241N-C404F-P406A-L448Y; -A241N-C404L; -A241N-C404L-L448F; -A241N-C404L-L448W; -A241N-C404L-L448Y; -A241N-C404L-P406A; -A241N-C404L-P406A-L448F; -A241N-C404L-P406A-L448Y; -A241D-C404F-L446I-L448W; -A241D-C404F-L448W; -A241D-C404F-P406A-L448W; -A241D-C404F-P406S-L448W; -A241D-C404L-P406A-G443D-L448W; -A241D-C404L-P406A-L446V-L448W; -A241D-C404L-P406A-L446V-L448W-T450M; -A241D-C404L-P406A-L448W; -A241D-C404L-P406A-L448W-T450M; -A241D-C404M-L448W; -A241D-C404M-P406A-L448W; -A241D-F401Y-C404F-L446I-L448W; -A241D-F401Y-C404F-L448W; -A241D-F401Y-C404F-P406A-L448W; -A241D-F401Y-C404M-L448W; -A241D-F401Y-C404M-P406A-L448W; -A241D-F401Y-S403G-C404F-L446I-L448W; -A241D-F401Y-S403G-C404F-L448W; -A241D-F401Y-S403G-C404M-L448W; -A241D-F401Y-S403P-C404F-L446I-L448W; -A241D-F401Y-S403P-C404F-L448W; -A241D-F401Y-S403P-C404M-P406A-L448W; -A241D-G402A-C404L-P406A-L446V-L448W; -A241D-G402A-C404L-P406A-L446V-L448W-T450M; -A241D-G402A-C404L-P406A-L448W; -A241D-G402A-C404L-P406A-L448W-T450M; -A241D-G402A-S403C-C404L-P406A-L446V-L448W; -A241D-G402A-S403C-C404L-P406A-L446V-L448W-T450M;-A241D-G402A-S403C-C404L-P406A-L448W; -A241D-G402A-S403C-C404L-P406A-L448W-T450M; -A241D-G402A-S403V-C404L-P406A-L446V-L448W; -A241D-G402A-S403V-C404L-P406A-L446V-L448W-T450M;-A241D-G402A-S403V-C404L-P406A-L448W; -A241D-G402A-S403V-C404L-P406A-L448W-T450M; -A241D-S403C-C404L-P406A-L446V-L448W; -A241D-S403C-C404L-P406A-L446V-L448W-T450M; -A241D-S403C-C404L-P406A-L448W; -A241D-S403C-C404L-P406A-L448W-T450M; -A241D-S403G-C404F-L446I-L448W; -A241D-S403G-C404F-L448W; -A241D-S403G-C404F-P406A-L448W; -A241D-S403G-C404M-P406A-L448W; -A241D-S403P-C404F-L446I-L448W; -A241D-S403P-C404F-L448W; -A241D-S403P-C404F-P406A-L448W; -A241D-S403P-C404M-L448W; -A241D-S403P-C404M-P406A-L448W; -A241D-S403V-C404L-P406A-L446V-L448W; -A241D-S403V-C404L-P406A-L446V-L448W-T450M;-A241D-S403V-C404L-P406A-L448W; -A241D-S403V-C404L-P406A-L448W-T450M; -A241N-C404F-L405H-P406A-L448W; -A241N-C404F-P406A-L448W; -A241N-C404L-P406A-L446C-L448W; -A241N-C404L-P406A-L446V-L448W; -A241N-C404L-P406A-L448W; -A241N-C404L-P406A-L448W-L449I; -A241N-C404L-P406A-L448W-T450M; -A241N-C404L-P406A-L448W-T450Q; -A241N-C404M-L448W; -A241N-C404M-P406A-L448W; -A241N-S403C-C404L-P406A-L448W; -A241N-S403N-C404L-P406A-L448W; -A241N-S403V-C404L-P406A-L448W; -P85L-A241N-C404M-L448W-T450M; -A241D-S403C-C404L-P406A-G443D-L448W; -A241D-S403C-C404L-P406A-G443H-L448W; -A241D-S403C-C404L-P406A-G443N-L448W; -A241D-S403C-C404L-P406A-L448W-L449I; -A241D-S403C-C404L-P406A-P444A-L448W; -A241D-S403C-C404L-P406A-P444H-L448W; -A241D-S403C-C404L-P406A-P444L-L448W; -A241D-G402A-S403C-C404L-P406A-G443H-L448W; -A241D-G402A-S403C-C404L-P406A-G443S-L448W; -A241D-G402A-S403C-C404L-P406A-L446M-L448W; -A241D-G402A-S403C-C404L-P406A-P444F-L448W; -A241D-G402A-S403C-C404L-P406A-P444H-L448W; -A241D-S403H-C404L-P406A-L448W-T450M; -A241D-S403C-C404L-P406A-G443A-L448W-T450M; -A241D-S403C-C404L-P406A-G443F-L448W-T450M; -A241D-S403C-C404L-P406A-G443Y-L448W-T450M; -A241D-S403C-C404L-P406A-P444A-L448W-T450M; -A241D-S403C-C404L-P406A-P444F-L448W-T450M; -A241D-S403C-C404L-P406A-P444T-L448W-T450M; -A241D-S403V-C404L-P406A-G443D-L446V-L448W; -A241D-S403V-C404L-P406A-G443D-L448W; -A241D-S403V-C404L-P406A-G443A-L448W-T450M; -A241D-S403V-C404L-P406A-G443D-L448W-T450M; -A241D-S403V-C404L-P406A-G443F-L448W-T450M; -A241D-S403V-C404L-P406A-G443N-L448W-T450M; -A241D-S403V-C404L-P406A-G443S-L448W-T450M; -A241D-S403V-C404L-P406A-V445L-L448W-T450M; -A241D-C404L-P406A-G443F-L446V-L448W-T450M; -A241D-C404L-P406A-L446V-L448W-T450A; -A241D-S403C-C404L-P406A-G443A-L446V-L448W-T450M; -A241D-S403C-C404L-P406A-G443S-L446V-L448W-T450M; -A241D-S403C-C404L-P406A-G443W-L446V-L448W-T450M; -A241D-S403C-C404L-P406A-G443Y-L446V-L448W-T450M; -H198Q-A241D-S403C-C404L-P406A-G443F-L446V-L448W-T450M;-A241D-S403C-C404L-P406A-P444H-L446V-L448W-T450M; -A241D-S403C-C404L-P406A-V408I-L446V-L448W-T450M; -A241D-S403C-C404L-P406A-L446M-L448W-T450M; -A241D-S403V-C404L-P406A-G443D-L446V-L448W-T450M; -A241D-S403V-C404L-P406A-G443F-L446V-L448W-T450M; -A241D-S403V-C404L-P406A-G443Y-L446V-L448W-T450M; -A241D-S403V-C404L-P406A-L446V-L448W-T450H; -A241D-S403A-C404L-P406A-L446V-L448W-T450M; -A241D-S403G-C404L-P406A-L446V-L448W-T450M; -A241D-S403V-C404L-P406A-V408I-L446V-L448W-T450M; -A241D-S403V-C404L-P406A-L446A-L448W-T450M; -A241D-S403V-C404L-P406A-L446M-L448W-T450M; -A241D-S403C-C404L-P406A-G443D-L448W-L449I; -A241D-S403C-C404L-P406A-P444H-L446M-L448W-T450M; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-G443D-P444A-L448W; -A241D-S403C-C404L-P406A-G443Y-P444H-L446M-L448W-T450M;-A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M;-A241D-S403C-C404L-P406A-G443Y-L446M-L448W-T450M; -A25E-A241D-S403C-C404L-P406A-L448W; -A66H-A241D-S403C-C404L-P406A-L448W; -A80S-A241D-S403C-C404L-P406A-L448W; -E24A-A241D-S403C-C404L-P406A-L448W; -E24D-A241D-S403C-C404L-P406A-L448W; -E24L-A241D-S403C-C404L-P406A-L448W; -E24V-A241D-S403C-C404L-P406A-L448W; -G237D-A241D-S403C-C404L-P406A-L448W; -G237P-A241D-S403C-C404L-P406A-L448W; -A241D-S403C-C404L-P406A-G443A-L448W; -I236L-A241D-S403C-C404L-P406A-L448W; -I236V-A241D-S403C-C404L-P406A-L448W; -A241D-I296Q-S403C-C404L-P406A-L448W; -K214T-A241D-S403C-C404L-P406A-L448W; -N64H-A241D-S403C-C404L-P406A-L448W; -A241D-S403C-C404L-P406A-L448W-P479C; -A241D-S403C-C404L-P406A-L448W-P479I; -A241D-S403C-C404L-P406A-L448W-P479L; -A241D-S403C-C404L-P406A-L448W-P479M; -A241D-S403C-C404L-P406A-L448W-P479S; -A241D-S403C-C404L-P406A-L448W-P479T; -A241D-S403C-C404L-P406A-L448W-P479V; -A241D-S403C-C404L-P406A-L448W-R496L; -S175E-A241D-S403C-C404L-P406A-L448W; -A241D-S403C-C404L-P406A-L448W-A473S; -S86N-A241D-S403C-C404L-P406A-L448W; -S86Y-A241D-S403C-C404L-P406A-L448W; -V240N-A241D-S403C-C404L-P406A-L448W; -V240N-A241D-S403C-C404L-P406A-L448W-P479V; -A66H-K214T-G237P-A241D-S403C-C404L-P406A-L448W; -K214T-G237P-A241D-I296Q-S403C-C404L-P406A-L448W; -K214T-G237P-A241D-I296Q-S403C-C404L-P406A-L448W-P479V; -K214T-A241D-S403C-C404L-P406A-L448W-R496L; -V240N-A241D-S403C-C404L-P406A-L448W-R496L; -K214T-G237P-V240N-A241D-I296Q-S403C-C404L-P406A-L448W; -A66H-A241D-S403C-C404L-P406A-L448W-P479V; -A66H-K214T-G237P-V240N-A241D-S403C-C404L-P406A-L448W-P479V;-A66H-K214T-A241D-S403C-C404L-P406A-L448W-P479V; -G237P-A241D-I296Q-S403C-C404L-P406A-L448W-P479V; -A66H-K214T-G237P-A241D-S403C-C404L-P406A-L448W-P479V; -A241D-I296Q-S403C-C404L-P406A-L448W-P479V; -A66H-K214T-A241D-I296Q-S403C-C404L-P406A-L448W; -K214T-A241D-S403C-C404L-P406A-G443N-L448W; -A66H-A241D-I296Q-S403C-C404L-P406A-L448W; -K214T-A241D-I296Q-S403C-C404L-P406A-L448W; -G237P-A241D-S403C-C404L-P406A-L448W-P479V; -A66H-K214T-A241D-I296Q-S403C-C404L-P406A-L448W-P479V; -A66H-G237P-V240N-A241D-S403C-C404L-P406A-L448W-P479V; -A66H-G237P-A241D-S403C-C404L-P406A-L448W-P479V; -K214T-A241D-I296Q-S403C-C404L-P406A-L448W-P479V; -A66H-A241D-I296Q-S403C-C404L-P406A-L448W-P479V; -K214T-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -K214T-G237P-A241D-S403C-C404L-P406A-L448W-P479V; -M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -A241D-S403C-C404L-P406A-V408C-G443F-L448W-T450M; -A241D-S403C-C404L-P406A-V408L-G443F-L448W-T450M; -A241D-S403C-C404L-P406A-G443F-V445L-L448W-T450M; -A241D-S403C-C404L-P406A-G443F-V445S-L448W-T450M; -A241D-S403C-C404L-P406A-G443F-V445T-L448W-T450M; -A241D-S403C-C404L-P406A-G443D-V445T-L448W; -M197V-A241D-S403C-C404L-P406A-G443D-P444A-L448W; -A241D-S403C-C404L-L405I-P406A-G443D-L448W-L449I; -M197V-A241D-S403C-C404L-P406A-G443D-L448W-L449I; -A241D-S403C-C404L-P406A-G443D-V445L-L448W-L449I; -A241D-S403C-C404L-P406A-G443A-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-G443F-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-G443L-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-G443S-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-G443D-P444H-L448W; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V; -M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-C404L-L405M-P406A-G443F-L446V-L448W-L449M-T450M; -A241D-S403Q-C404L-P406A-G443F-L446V-L448W-T450M; -A241D-S403C-C404L-P444H-L448W-T450M; -A241D-S403C-C404L-P406S-P444H-L448W-T450M; -L195I-A241D-S403C-C404L-P406A-P444H-L448W-T450M; -M197V-A241D-S403C-C404L-P406A-P444H-L448W-T450M; -A241D-S403C-C404L-P406A-Q407R-P444H-L448W-T450M; -A241D-S403C-C404L-P406A-Q407S-P444H-L448W-T450M; -A241D-S403C-C404L-P406A-V408I-P444H-L448W-T450M; -L195I-A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M;-M197V-A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M;-A241D-S403C-C404L-P406A-V408I-P444H-V445C-L446M-L448W-T450M;-M197V-A241D-S403C-C404L-P406A-G443Y-P444H-L446M-L448W-T450M;-M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V; -M197V-A241D-S403C-C404L-P406A-G443S-P444H-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-E441R-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-D442L-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-D442R-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-D442M-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-D442A-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-D442S-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-D442G-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-G443D-P444H-V445T-L448W-L449I; -A241D-S403C-C404L-P406A-Q407C-G443D-P444H-L448W-L449I; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454A; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454W; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454V; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454M; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454H; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454T; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454G; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454K; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454Q; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454L; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A459Y; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A459N; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A460N; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A460L; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A460M; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-A460R; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-R461V; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-R461S; -E154D-A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-L302R-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-E339H-A363G-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-E339H-R390D-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-E339H-R390L-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-E339H-R390N-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-E339H-R390Q-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-E339H-R391D-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-E339H-R391W-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-E339H-E394Q-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -V3M-A241D-E339H-E394T-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A241D-E339H-G398R-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -A129V-A241D-E339H-G398C-S403C-C404L-P406A-G443D-P444H-L448W-L449I;-A241D-E339H-S403C-C404L-P406A-V408L-G443D-P444H-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-V408M-G443D-P444H-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-E441S-G443D-P444H-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-D442H-G443D-P444H-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-D442R-G443D-P444H-L448W-L449I; -I168V-A241D-E339H-S403C-C404L-P406A-G443D-P444H-V445L-L448W-L449I;-A241D-E339H-S403C-C404L-P406A-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-Y452F; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-T453L; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454H; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454K; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454S; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454T; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454W; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-R461V-P479S;-A241D-S403C-C404L-P406A-Q407A-G443N-L448W; -A241D-S403C-C404L-P406A-D442A-G443N-L448W; -A241D-S403C-C404L-P406A-G443N-L448W-T450H; -A241D-S403C-C404L-P406A-G443N-L448W-T453R; -A241D-S403C-C404L-P406A-G443N-L446M-L448W; -A241D-E339H-S403C-C404L-P406A-E441K-G443D-P444H-L446M-L448W-L449I;-M197V-G237A-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-G237D-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-G237N-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-G237P-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-D238H-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-D238R-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-D238S-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-D238W-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-L302A-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-L302K-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-L302M-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-L302R-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-A359V-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-G398R-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-E394C-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-E394D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-V396I-S403C-C404L-P406A-G443F-L448W-T450M; -V35I-M197V-A241D-S403C-C404L-P406A-Q407I-G443F-L448W-T450M; -M197V-A241D-S403C-C404L-P406A-V408A-G443F-L448W-T450M; -Y2N-M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M; -M197V-A241D-S403C-C404L-P406A-R439C-G443F-L448W-T450M; -M197V-A241D-S403C-C404L-P406A-F440L-G443F-L448W-T450M; -M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-A460F; -M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-A460L; -M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-A460R; -M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-P454T; -M197V-A241D-S403C-C404L-P406A-G443F-L448W-T450M-A462V; -M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-A459D; -A241D-S403C-C404L-P406A-G443D-L448W-L449I-A459G; -A241D-S403C-C404L-P406A-G443D-L448W-L449I-A459R; -A241D-S403C-C404L-P406A-G443Y-L448W-T450M-A460E; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-A460G; -M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-A460G-A462V;-A241D-S403C-C404L-P406A-G443Y-L448W-T450M-A460L; -S403C-C404M-P406A-Q407T-G443Y-L446I-L448W-T450H-A460L; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-A460Q; -A241D-S403C-C404L-P406A-G443Y-L448W-T450M-A462C; -M197V-S403C-C404M-P406A-D442N-G443Y-L446I-L448W-T450H-A462C; -A241D-S403C-C404L-P406A-G443Y-L448W-T450M-A462V; -A241D-S403C-C404L-P406A-E441G-G443D-L448W-L449I; -Q208L-A241D-S403C-C404L-P406A-V408I-G443R-P444H-L446M-L448W-T450M;-A241D-S403C-C404L-P406A-V408I-G443W-P444H-L446M-L448W-T450M; -A241D-S403C-C404L-P406A-G443D-L448W-L449I-H458G; -M197V-A241D-S403C-C404L-P406A-G443Y-L448W-T450M; -A241D-S403C-C404L-P406A-G443D-L448W-L449I-P454K; -M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-P454K; -A241D-S403C-C404L-P406A-G443D-L448W-L449I-P454R; -M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-P454R; -A241D-S403C-C404L-P406A-G443D-L448W-L449I-Q455S; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-R461S; -M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-T450H; -A241D-S403C-C404L-P406A-G443D-L448W-L449I-T450V; -M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449V-T450V; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-T453R; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-T453S; -M197V-A241D-S403C-C404L-P406A-G443D-P444H-L448W; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-Y452F; -M5I-A241D-S403C-C404L-P406A-G443Y-L448W-T450M; -M197V-A241D-S403C-C404L-P406A-G443F-L446M-L448W-T450M; -A241D-E339H-A343S-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-A350S-S403C-C404L-P406A-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-A395E-S403C-C404L-P406A-A426V-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-D442S-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-D442T-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-G443H-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-E441R-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-I347C-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R; -V3L-A241D-L302Q-E339H-S403C-C404L-P406A-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-S403C-C404L-L405T-P406A-G443D-P444H-L446M-L448W-L449I; -M5I-A241D-E339H-S403C-C404L-P406A-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R-Q455A; -A241D-E339H-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R-Q455N; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R-A459E; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R-A459M; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R-A459Q; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R-A459T; -A241D-S403C-C404L-P406A-G443N-P444H-L448W-L449I-P454R; -A241D-S403C-C404L-P406A-E441G-G443D-P444H-L448W-L449I-P454R; -A241D-S403C-C404L-P406A-G443D-P444F-L448W-L449I-P454R; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R-H458F; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R-H458N; -A241D-I296Q-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R; -A241D-L302A-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R; -A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-T453S-P454R; -V196I-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R; -A241D-V305I-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R; -A241D-V305T-S403C-C404L-P406A-G443D-P444H-L448W-L449I-P454R; -M197V-G237A-A241D-S403C-C404L-P406A-E441G-G443F-L448W-T450M; -M197V-G237A-A241D-S403C-C404L-P406A-E441H-G443F-L448W-T450M; -M197V-G237A-A241D-S403C-C404L-P406A-E441T-G443F-L448W-T450M; -M197V-A241D-S403C-C404L-P406A-F440L-G443F-L446M-L448W-T450M; -M197V-A241D-H277Y-S403C-C404L-P406A-F440L-G443F-L448W-L449I-T450M; -M197V-G237A-A241D-S403C-C404L-P406A-G443F-P444H-L448W-T450M; -M197V-G237A-A241D-S403C-C404L-P406A-G443F-P444I-L448W-T450M; -M197V-A241D-S403C-C404L-P406A-Q407R-F440L-G443F-L448W-T450M; -V6M-M197V-D238H-A241D-S403C-C404L-P406A-G443F-L448W-T450M-T453C; -M197V-D238H-A241D-S403C-C404L-P406A-G443F-L448W-T450M-T453R; -M197V-D238H-A241D-S403C-C404L-P406A-G443F-L448W-T450M-Y452F; -A241D-S403C-C404L-P406A-P444H-L446M-L448W-T450M-Y452F; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-Y452F-Q455H; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-P447Q-L448W-T450M-A460G; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-Q455K-R461S; -A241D-S403C-C404L-P406A-V408I-P444H-L446M-L448W-T450M-Q455V-R461S; -A241D-E339H-H366F-S403C-C404L-P406A-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-H366F-S403C-C404L-P406A-G443D-P444H-L446M-L448W; -A241D-E339H-H366I-S403C-C404L-P406A-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-L368I-S403C-C404L-P406A-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-L368M-S403C-C404L-P406A-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-L368M-S403C-C404L-L405M-P406A-G443D-P444H-L446M-L448W-L449I; -A241D-E339H-A395V-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-A460F; -A241D-E339H-E349M-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-E441H-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-E441N-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-E441R-D442N-G443D-P444H-L448W-L449I-P454R; -A126V-A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-H458E; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-H458G; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-H458L; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-H458Q; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-H458R; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-H458S; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-H458Y; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449V-P454R; -A241D-L302C-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-L405V-P406A-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-Q407R-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-Q407S-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-Q455E; -H36Y-A241D-R298S-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454A; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454D; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454L; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454S; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-R461A; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-R461L; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-R461M; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-R461Q; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-R461S; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-P454R-R461V; -A241D-E339H-S403C-C404L-P406A-D442N-G443D-P444H-L448W-L449I-T450S-P454R; -A241D-S403C-C404L-P406S-G443D-P444H-L448W-L449I; -M5I-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I; -V166D-A241D-S403C-C404L-P406A-G443D-P444H-L448W-L449I-Y452F.

2. A nucleic acid molecule encoding the 3-methylcrotonate decarboxylase variant of claim 1.

3. A vector comprising the nucleic acid molecule of claim 2.

4. A host cell comprising the nucleic acid molecule of claim 2 or the vector of claim 3.

5. Use of the 3-methylcrotonate decarboxylase variant of claim 1 or the host cell of claim 4 for converting 3-methylcrotonate into isobutylene.

6. A method for enzymatically converting 3-methylcrotonate to isobutylene by incubating 3-methylcrotonate with the 3-methylcrotonate decarboxylase variant of claim 1.

7. The method of claim 6, wherein the enzymatic conversion is performed in vitro.

8. A composition comprising the 3-methylcrotonate decarboxylase variant of claim 1, the nucleic acid molecule of claim 2, the vector of claim 3 or the host cell of claim 4.

9. A composition comprising the 3-methylcrotonate decarboxylase variant of claim 1, the nucleic acid molecule of claim 2, the vector of claim 3 or the host cell of claim 4, and 3-methylcrotonate.

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