37 results about "Amino-acid racemase" patented technology

The invention discloses fructose amino acid oxidase which has an amino acid sequence shown as SEQID.No.1 (sequence identifier number 1) or has above 80% homology with the amino acid sequence. One or more amino acid residues in corresponding positions of amino acid selected from (a) to (f) are substituted. The obtained fructose amino acid oxidase has higher thermostability: (a) 59-site glutamic acid, (b) 98-site glutamic acid, (c) 225-site glycine, (d) 277-site lysine, (e) 283-site glutamic acid and (f) 355-site aspartic acid. The invention further discloses a preparation method of the oxidase and a kit comprising the oxidase and used for determining glycatedalbumin. The kit has higher thermostability and can accurately determine the glycatedalbumin.

The invention relates to a method for preparing a chiral compound based on splitting by adopting a biological enzyme preparation, in particular to a method for preparing an L-tertiary leucine compound by a two enzyme system. The method prepares the chiral L-tertiary leucine compound of the formula III by using the reaction of an N-acylating tertiary leucine compound of the formula II in water or a buffer solvent at 15 to 60 DEG C in the presence of the two enzyme system. The biological enzyme is a mixed enzyme of an acylating amino acid racemase (alanine racemase) and a hydrolase; and the preparation reaction equation is as follows, wherein X is any group of OH, NH2, NR1R2 and OR3 (wherein R1, R2, R3 are a C1-C5 straight chain, a branch chain and a one, two or three-halogen substituted alkane respectively). The invention can be implemented at room temperature and ensures simple operation and no pollution, while remarkably lowering the production cost.

A method of producing male or female sterile plants comprising the steps of transforming plant material with a polynucleotide which encodes at least one enzyme which reacts with a non-phytotoxic substance to produce a phytotoxic one, and regenerating the thus transformed material into a plant, wherein the said non-phytotoxic substance is applied to the plant up to the time of male or female gamete formation and / or maturation, so that the non-phytotoxic substance provides for the production of a phytotoxic one which selectively prevents the formation of or otherwise renders the said gametes non-functional, wherein the enzyme is expressed preferentially in either male or female reproductive structures, characterised in that (i) the non-phytotoxic substance is selected from the group consisting of ester derivatives of non-phosphonate herbicides which herbicides are directly phytotoxic to non-green tissue, D-alpha amino acids, peptide derivatives of non-protein D-alpha amino acids, S-enantiomers of aryloxyphenoxypropionates and S-enantiomers of ester derivatives of aryloxyphcnoxypropionatcs and (ii) the enzyme is selected from the group consisting of carboxylesterases, D-amino acid oxidases, D-amino acid dehydrogenases, D-amino acid racemases, 2-arylpropionyl-CoA epimerases, alpha-methylacyl-CoA racemases, thioesterases and acyl-CoA synthetases.

The invention provides a Delta 5 fatty acid desaturase from ocean microalgae, and coding gene and an application thereof. The inventive Delta 5 fatty acid desaturase has amino acid sequence shown in SEQ ID NO.2 or amino acid subjected to substitution, deletion or addition of one or more amino acid residues of the amino acid sequence and having the same functions. The inventive Delta 5 fatty acid desaturase can effectively catalyze the conversion of ETA(20:4 Delta 8,11,14,17) to EPA(20:5 Delta 5,8,11,14,17), and has the advantages of high specificity of substrate and high enzyme activity.

A method of preventing or inhibiting infection by a parasite or virus in vivo comprises administering to a human in need thereof a parasite or virus mitogen in a sub-mitogenic amount sufficient to induce a protective immune response against the parasite or virus in the human.

The invention discloses alpha-conus polypeptides and use thereof. The invention provides seven polypeptides: a polypeptide I of which the amino acid sequence is represented by a sequence 7 in a sequence table and in which the last amino acid residue is amidated; a polypeptide II of which the amino acid sequence is represented by a sequence 8 in the sequence table and in which the last amino acid residue is amidated; a polypeptide III of which the amino acid sequence is represented by a sequence 9 in the sequence table and in which the last amino acid residue is amidated; a polypeptide IV of which the amino acid sequence is represented by a sequence 10 in the sequence table and in which the last amino acid residue is amidated; a polypeptide V of which the amino acid sequence is representedby a sequence 11 in the sequence table and in which the last amino acid residue is amidated; a polypeptide vI of which the amino acid sequence is represented by a sequence 12in the sequence table andin which the last amino acid residue is amidated; and a polypeptide VII of which the amino acid sequence is represented by a sequence 13 in the sequence table and in which the last amino acid residueis amidated. The result of activity tests, the seven polypeptides of the general formula (I) have pain relieving effect, alpha-conus polypeptides T-1, T-2, T-3 and T-4 have obvious pain-relieving activity, and the alpha-conus polypeptides T-5, T-6 and T-7 also have obvious pain-relieving effect, and the alpha-conus polypeptides have application values in pain-reliving aspect.

Amino acids, such as L-glutamine, L-arginine, L-tryptophan, L-histidine and L-glutamate are produced using a bacterium belonging to the genus Escherichia harboring a mutant glutamine synthetase in which the tyrosine amino acid residue corresponding to position 397 in a wild type glutamine synthetase is replaced with any of amino acid residues, preferably with phenylalanine.

The invention relates to a formaldehyde absorption board.The formaldehyde absorption board comprises a water-containing layer, wherein the aqueous solution of amino acid infiltrates the water-containing layer, a porous layer wraps the water-containing layer, a breathable waterproof layer wraps the porous layer, the porous layer is made of bentonite or activated carbon, the water-containing layer is made of cotton and sponges, and the aqueous solution of the amino acid is the aqueous solution of one or more of glycine, alanine, valine, leucine, tryptophan, methionine, proline, tyrosine, cysteine amino acid, asparagine, threonine, serine and glutamic acid.The formaldehyde absorption board has the advantages that the aqueous solution of the amino acid infiltrates the water-containing layer, the aqueous solution of the amino acid can outwardly infiltrate to enter the pores of the porous layer and contact with air, and the amino acid reacts with the formaldehyde so as to remove the formaldehyde; the formaldehyde absorption board is of a board shape, the contact area with the air can be increased, and the formaldehyde removing effect is increased.

This application relates to laccase variants and uses thereof as eco-friendly biocatalysts in various industrial processes. More in particular, the disclosure relates to a polypeptide with laccase activity comprising an amino acid sequence that is more than 80% identical to the amino acid sequence according to SEQ ID NO: 1, wherein the polypeptide comprises a non-polar amino acid, preferably an amino acid residue selected from the group consisting of proline, alanine, glycine and valine at a position corresponding to amino acid 113 of SEQ ID NO: 1.

The invention relates to a synthesis method of D-threonine (I). The method comprises the following steps: preparing D-allothreonine (V) from L-threonine (VI) serving as a raw material through racemization of amino acid racemase, action of L-threonine deaminase and purification sequentially; performing esterification on D-allothreonine (V) serving as a starting material to obtain an intermediate (IV); protecting amino by using benzoyl to obtain a compound of a formula (III); performing intramolecular cyclization on the compound of the formula (III) in the presence of sulfoxide chloride and turning over the spatial configuration of hydroxyl to obtain an oxazoline intermediate (II); performing ring opening on the intermediate (II) under the action of acid and removing a protecting group to obtain D-threonine (I). The synthesis method of D-threonine (I) is smart in design, the starting materials are cheap and readily available, the process flow is simple and practical, and a new method is provided for producing D-threonine on a large scale.

The invention relates to a preparation method of D-amino acid. The method comprises the steps of 1, the constructing of recombinant bacteria: an N-acetyl-D-aminoacylase gene is cloned, and the gene isconnected to a pET series carrier or a pKK 223-3 carrier and transformed to BL21 (DE3) host bacteria to construct D acylase recombinant bacteria (NLase); an N-acetyl-amino acid racemase gene is cloned, the gene is connected to the pET series carrier of the pKK223-3 carrier, transformed to the BL21(DE3) host bacteria to construct N-acetylamino acid racemase recombinant bacteria (NAAR); 2, recombinant bacteria fermentation; 3, immobilized enzyme preparation; 4, immobilized enzyme transforming combining with membrane separation; 5, product crystallization. By means of the method, the cost of theenzyme is reduced, the inhibition on the racemase of byproduct acetic acid is reduced, meanwhile, the transformation solution has little impurity, the separation and purification are simple, the yield is high, the product quality is good, the e.e. value of the obtained D-amino acid reaches 99.9% or above, the content is 99% or above, and the mole yield reaches 85% or above.

The present invention provides a novel peptide having bone formation-promoting effect and chondrocyte growth-promoting effect, in particular, a peptide having osteoblast growth-promoting activity, having 100 amino acid residues or less comprising an amino acid sequence selected from(a) Val-Asn-Pro-Glu-Ser-Glu-Glu-Glu-Asp-Glu-Ser-Ser-Pro-Tyr-Glu (SEQ ID NO: 1),(b) an amino acid sequence derived from the amino acid sequence (a) by conservative substitution or deletion of 1 to 3 amino acids, and(c) an amino acid sequence consisting of at least four contiguous amino acids of the amino acid sequence (a) or (b), ora derivative thereof or a salt thereof.

The invention belongs to the field of biotechnology, and relates to a method for preparing D-amino acid and alpha keto acid. The method includes the first step of recombinant construction: conductingwhole gene synthesis to obtain an L-amino acid deaminase gene LAAD and connecting an expression vector to be transformed into an expression strain to construct a recombinant PMLAAD; conducting whole gene synthesis to obtain an amino acid racemase gene AAR and connecting the expression vector to be transformed into the expression strain to construct a recombinant AAR; the second step of fermentation; the third step of enzyme catalysis; the fourth step of isolation and purification. The alpha-keto acid calcium and the D-amino acid are produced by enzyme catalysis, and both products have economicvalue and high product quality, so that the production cost is greatly reduced.

The invention discloses engineering bacteria for producing D-tryptophan and a construction method and a purpose of producing D-tryptophan. The construction method comprises the following steps: transferring an acylated amino acid racemase mutant gene and a N-acetyl-D-amino acid acyl hydrolase mutant gene in escherichia coli, and constructing the engineering bacteria for producing D-tryptophan. Theconstruction method optimizes the N-acetyl-D-amino acid acyl hydrolase mutant gene and the acylated amino acid racemase mutant gene, the acyl hydrolysis activity of the N-acetyl-D-tryptophan by the N-acetyl-D-amino acid acyl hydrolase and the racemization activity of the N-acetyl-L tryptophan by the acylated amino acid racemase are increased, and the output and the product quality of the D-tryptophan are increased. Two types of enzymes can be expressed by the same engineering bacterial strain, the fermentation cost is saved, and the production technology is simplified.

The invention relates to feed additives containing dipeptides or salts thereof, in which one amino acid residue of the dipeptide is a DL-methionyl residue and the other amino acid residue of the dipeptide is an amino acid in the L-configuration selected from lysine, threonine, tryptophan, histidine, valine, leucine, isoleucine, phenylalanine, arginine, cysteine and cystine; feed mixtures containing these additives and method of producing the dipeptides.

A method of preventing or inhibiting infection by a parasite or virus in vivo comprising administering to a human in need thereof a parasite or virus mitogen in a sub-mitogenic amount sufficient to induce a protective immune response against the parasite or virus in the human.

This application relates to laccase variants and uses thereof as eco-friendly biocatalysts in various industrial processes. More in particular, the disclosure relates to a polypeptide with laccase activity comprising an amino acid sequence that is more than 80% identical to the amino acid sequence according to SEQ ID NO: 1, wherein the polypeptide comprises a non-polar amino acid, preferably an amino acid residue selected from the group consisting of proline, alanine, glycine and valine at a position corresponding to amino acid 113 of SEQ ID NO: 1.

The invention discloses a method for producing DL-tyrosine by an enzyme, and a broad-spectrum amino acid racemase and use thereof. The method for producing DL-tyrosine by the enzyme comprises the following steps: S1, constructing a recombinant expression vector pET32a-PH0138 and transforming the recombinant expression vector into escherichia coli BL21(DE3) / pG-KJE8 to obtain a recombinant engineering bacteria BBAR; S2, fermenting the recombinant engineering bacteria BBAR expressing a BAR enzyme to obtain wet bacteria body; S3, suspending the wet bacteria body and crushing the bacteria with a crushing solution containing crude enzyme liquid of a broad-spectrum amino acid racemase; and S4, adding L-tyrosine and PLP into the crude enzyme liquid obtained in step S3, conducting stirring and converting until specific rotation is 0 degree and terminating the reaction to obtain a DL-tyrosine aqueous solution. The method has advantages of low raw material price, high conversion rate, simple post-treatment and high product quality, and is suitable for industrial mass production.

The invention discloses a method for synthesizing dipeptide with glutamic acid as the first amino acid residue. The method comprises the following steps: protecting the amino group of glutamic acid-5 methyl ester serving as an initial raw material by using carbobenzoxy; reacting with dicyclohexyl carbodiimide and N-hydroxy succinimide to prepare a high-purity midbody; further reacting with another group of amino acid under the alkali condition to obtain protected dipeptide; finally hydrogenating to obtain high-purity dipeptide which takes glutamic acid as the first amino acid residue. The method is environment-friendly, simple to operate, nearly free of waste discharge and beneficial to industrial production.

A culture method for pluripotent stem cells includes culturing pluripotent stem cells on a cell culture surface of a support by using a medium in which the concentration of 2-mercaptoethano is equal to or less than 10 μM in the presence of a polypeptide consisting of 40 to 450 amino acid residues, in which the polypeptide includes (1) a first domain including at least one amino acid sequence selected from the group consisting of an amino acid sequence represented by CSYYQSC (SEQ ID NO: 1) and an amino acid sequence represented by RGD and (2) a second domain including (2-i) an amino acid sequence which is represented by PRPSLAKKQRFRHRNRKGYRSQRGHSRGRNQN (SEQ ID NO: 2), (2-ii) an amino acid sequence which shares sequence identity of equal to or higher than 50% with the amino acid sequence represented by SEQ ID NO: 2 and exhibits adsorbability with respect to the cell culture surface of the support, or (2-iii) an amino acid sequence which is formed by the addition, substitution, or deletion of 1 to 30 amino acids in the amino acid sequence represented by SEQ ID NO: 2 and exhibits adsorbability with respect to the cell culture surface of the support.

The present invention relates to an amide hydrolase which is with excellent thermostability and stereoselectively hydrolyzes an α-amino acid amide; a gene encoding the enzyme protein; a novel recombinant vector containing the gene; a transformant containing the recombinant vector; and a process for producing an L-α-amino acid using the transformant.

The invention discloses a method for enzymatically producing DL-tyrosine and a broad-spectrum amino acid racemase and its application. The method for enzymatically producing DL-tyrosine comprises the following steps: S1, constructing a recombinant expression vector pET32a-PH0138, Transform into Escherichia coli BL21(DE3) / pG‑KJE8 to obtain the recombinant engineered bacteria BBAR; S2, ferment the recombinant engineered bacteria BBAR expressing BAR enzyme to obtain wet cells; S3, suspend the wet cells and perform crushing treatment, crush The solution is a crude enzyme solution containing a broad-spectrum amino acid racemase; S4, adding L-tyrosine and PLP to the crude enzyme solution obtained in step S3, stirring and converting, until the specific rotation is 0°, the reaction is terminated, and the obtained DL‑Tyrosine in water. The method has the advantages of low raw material price, high conversion rate, simple post-treatment, high product quality, and is suitable for large-scale industrial production.

A method of producing male or female sterile plants comprising the steps of transforming plant material with a polynucleotide which encodes at least one enzyme which reacts with a non-phytotoxic substance to produce a phytotoxic one, and regenerating the thus transformed material into a plant, wherein the said non-phytotoxic substance is applied to the plant up to the time of male or female gamete formation and / or maturation, so that the non-phytotoxic substance provides for the production of a phytotoxic one which selectively prevents the formation of or otherwise renders the said gametes non-functional, wherein the enzyme is expressed preferentially in either male or female reproductive structures, characterised in that (i) the non-phytotoxic substance is selected from the group consisting of ester derivatives of non-phosphonate herbicides which herbicides are directly phytotoxic to non-green tissue, D-alpha amino acids, peptide derivatives of non-protein D-alpha amino acids, S-enantiomers of aryloxyphenoxypropionates and S-enantiomers of ester derivatives of aryloxyphcnoxypropionatcs and (ii) the enzyme is selected from the group consisting of carboxylesterases, D-amino acid oxidases, D-amino acid dehydrogenases, D-amino acid racemases, 2-arylpropionyl-CoA epimerases, alpha-methylacyl-CoA racemases, thioesterases and acyl-CoA synthetases.

An isoamylase having improved heat resistance and an industrial method for producing maltose from starch.The isoamylase is an isoamylase consisting of the amino acid sequence represented by SEQ ID NO: 1 or an isoamylase resulting from deletion, substitution, or insertion of one to several amino acid residues in the amino acid sequence represented by SEQ ID NO: 1, wherein at least valine at amino acid number 515 and methionine at amino acid number 570 are mutated to other amino acids.

The invention discloses an amino acid racemase and its application in catalyzing the racemization of amino acids, belonging to the field of biotechnology. The amino acid racemase is a polypeptide I having an amino acid sequence as shown in SEQ ID NO.1 or a polypeptide II having at least 70% identity with the amino acid sequence shown in SEQ ID NO.1 and having the function of catalyzing amino acid racemization. Amino acid racemase has racemization activity for various amino acid isomers such as Leu and Met, and is thermostable, so it can be applied to enzyme-catalyzed digestion of L-Leu / D-Leu, L-Met / D-Met Rotation is of great significance for the mutual transformation of amino acid enantiomers.

An isoamylase having improved heat resistance and an industrial method for producing maltose from starch.The isoamylase is an isoamylase consisting of the amino acid sequence represented by SEQ ID NO: 1 or an isoamylase resulting from deletion, substitution, or insertion of one to several amino acid residues in the amino acid sequence represented by SEQ ID NO: 1, wherein at least valine at amino acid number 515 and methionine at amino acid number 570 are mutated to other amino acids.

The present invention relates to a novel thermostable N-acylamino acid racemase (NAAAR) isolated from Deinococcus radiodurans NCHU1003, the coding sequence and the preparation thereof. The present invention also discloses the process for preparing highly optically pure L-amino acids, such as L-homophenylalanine (L-HPA) and the derivatives thereof, from N-protected amino acid by using the novel NAAAR combined with L-N-carbamoylase.

The invention discloses alpha-conus polypeptides and use thereof. The invention provides seven polypeptides: a polypeptide I of which the amino acid sequence is represented by a sequence 7 in a sequence table and in which the last amino acid residue is amidated; a polypeptide II of which the amino acid sequence is represented by a sequence 8 in the sequence table and in which the last amino acid residue is amidated; a polypeptide III of which the amino acid sequence is represented by a sequence 9 in the sequence table and in which the last amino acid residue is amidated; a polypeptide IV of which the amino acid sequence is represented by a sequence 10 in the sequence table and in which the last amino acid residue is amidated; a polypeptide V of which the amino acid sequence is representedby a sequence 11 in the sequence table and in which the last amino acid residue is amidated; a polypeptide vI of which the amino acid sequence is represented by a sequence 12in the sequence table andin which the last amino acid residue is amidated; and a polypeptide VII of which the amino acid sequence is represented by a sequence 13 in the sequence table and in which the last amino acid residueis amidated. The result of activity tests, the seven polypeptides of the general formula (I) have pain relieving effect, alpha-conus polypeptides T-1, T-2, T-3 and T-4 have obvious pain-relieving activity, and the alpha-conus polypeptides T-5, T-6 and T-7 also have obvious pain-relieving effect, and the alpha-conus polypeptides have application values in pain-reliving aspect.

The invention discloses a method for preparing gamma-carbonyl carboxylic acid, amino acid, amino acid ester and amide compounds. The method comprises the following steps: uniformly mixing a methylene-containing compound, an oxidizing agent and water to perform selective methylene carbon-hydrogen bond oxidation, so as to obtain at least one of gamma-carbonyl carboxylic acid, gamma-carbonyl amino acid and gamma-carbonyl amide compounds after the reaction is finished. The method is a methylene selective oxidation reaction which does not need a catalyst for catalysis and employs a persulfate as an oxidizing agent, and the reaction is successfully applied to oxidation of methylene carbon-hydrogen bonds of carboxylic acids, amino acids and amide compounds, excellent selectivity is obtained, and the method has important application value.

The present invention relates to a preparation method of D-amino acid, comprising the following steps: 1. Construction of recombinant bacteria: cloning N-acetyl-D-aminoacylase gene, connecting the gene into pET series vector or pKK223-3 vector, and transforming it into BL21 (DE3) host bacteria, construct D-acylase recombinant bacteria (NLase); clone N-acetyl-amino acid racemase gene, connect the gene into pET series vector or pKK223-3 vector, transform into BL21(DE3) host bacteria, construct N-acetylamino acid racemase recombinant bacteria (NAAR); 2. Fermentation of recombinant bacteria; 3. Preparation of immobilized enzyme; 4. Transformation of immobilized enzyme combined with membrane separation; 5. Product crystallization. The invention reduces the cost of the enzyme and reduces the inhibition of the by-product acetic acid on the racemase. At the same time, because the conversion liquid has few impurities, the separation and purification are simple, the yield is high, and the product quality is good. The obtained D-amino acid has an e.e. value of more than 99.9%, a content of more than 99%, and a molar yield of more than 85%.