210 results about "Specific enzyme" patented technology

The invention discloses an arginine decarboxylase diaA enzyme mutant and application thereof in preparation of butanediamine, and belongs to the field of bioengineering. According to the invention, rational charge overturning transformation is simultaneously carried out on a pentamer meridian oligomeric interface and a dimer latitudinal oligomeric interface, so that stable assembly and efficient catalysis of the decamer under the condition of neutral to alkaline pH (7.0-9.0) are realized. Wherein positive charges are introduced into a meridian interface to weaken electrostatic repulsion, and negative charges are introduced into a latitudinal interface to enhance dimer compactness and substrate transfer efficiency. The specific enzyme activity of the representative double mutant AdiAD110K / H736E at pH 8.0 is about 35 times that of a wild type, and the representative double mutant AdiAD110K / H736E keeps a complete decamer state in a pH range of 7.0-9.0. The yield of butanediamine is up to 145.9 g / L under the whole-cell catalysis of the mutant.

The invention discloses a rational copolymerization strategy for improving the stability of an oligomeric structure of acid-induced high-order oligomeric decarboxylase AdiA in a neutral to alkaline environment and application of the rational copolymerization strategy, and belongs to the field of bioengineering. According to the strategy, rational charge overturning transformation is carried out on a pentamer radial oligomeric interface and a dimer weft-wise oligomeric interface at the same time, and stable assembly and efficient catalysis of a decamer under the condition that the pH value is from 7.0 to 9.0 from neutral to alkaline are achieved. Wherein positive charges are introduced into a meridian interface to weaken electrostatic repulsion, and negative charges are introduced into a latitudinal interface to enhance dimer compactness and substrate transfer efficiency. The specific enzyme activity of the representative double mutant AdiAD471K / E467K / H736E is 45.5 times that of a wild type when the pH value is 8.0, and the representative double mutant AdiAD471K / E467K / H736E keeps a complete decamer state when the pH value is 7.0-9.0. The yield of butanediamine is up to 156.5 g / L by using the mutant to catalyze whole cells.

Provided are S-adenosylmethionine synthetase mutants and the use thereof, belonging to the technical field of biological enzyme engineering. Site-directed combinatorial mutations are performed on positions 189, 200, 234, 266 and 371 of S-adenosylmethionine synthetase MAT to obtain a series of mutants with improved enzyme activity, wherein the specific enzyme activity of I189V / V266H and V266H / N371R is increased by more than 10 times relative to the parent. The yields of S-adenosylmethionine synthesized by whole cells of recombinant bacteria expressing mutants I189V / V266H / N371R, V266H / Q234N / N371R and I189V / V266H / Q234N / N371R all reach 1550 mg / L or more. The provided enzyme mutants have broad application prospects in the production of S-adenosylmethionine and the construction of genetically engineered microorganisms for S-adenosylmethionine.

The invention discloses a mutant with improved catalytic activity of S-adenosylmethionine synthetase and application of the mutant, and belongs to the technical field of biological enzyme engineering. According to the present invention, the site 189, the site 234, the site 266 and the site 371 of the S-adenosylmethionine synthetase MAT are subjected to site-specific combinatorial mutation to obtain a series of mutants with improved enzyme activity, the I189V / V266H improvement is the most obvious, and the specific enzyme activity is 3.5833 + / -0.1373 U.mg <-1 >, which is improved by 1353.08% compared to the parent WT; and for a whole-cell catalysis system, the yield of S-ademetionine synthesized by the mutant I189V / V266H / Q234N / N371R reaches 1751.01 mg / L, and the increase is most obvious. The enzyme mutant provided by the invention has a wide application prospect in the production of S-adenosylmethionine and the construction of genetic engineering microorganisms of S-adenosylmethionine.

The application discloses a galactosyltransferase mutant and application thereof in preparation of flavonoid compounds, and belongs to the technical field of enzymology. The application provides a UDP-galactosyltransferase mutant, which is obtained by site-directed mutation of one amino acid in the amino acid sequence of wild-type galactosyltransferase VcUFGT into alanine (A). The effects of a series of mutants H82A, V139A, G141A, P186A, N245A, V282A and S307A are verified in the examples, the mutants can perform enzyme catalysis reaction with quercetin and UDP-galactoside as substrates, and generate flavonoid compound hyperoside, and the specific enzyme activity of the mutants is more than 1.5 times that of the wild type, thereby providing an effective application basis for biosynthesis of flavonoid compounds.

The invention discloses a glutathione bifunctional synthetase mutant with improved catalytic activity and application, and belongs to the field of gene engineering and fermentation engineering. A series of mutants with improved enzyme activity are obtained by carrying out site-specific combinatorial mutation on a site 61, a site 136, a site 485, a site 498 and a site 722 of the glutathione bifunctional synthetase GshFst, the specific enzyme activity reaches 13.58 U.mg <-1 >-27.34 U.mg <-1 >, the half-life period at 37 DEG C reaches 195-320 min, and the enzyme activity and the thermal stability are remarkably improved compared with those of a wild type. The enzyme mutant provided by the invention has a wide application prospect in the production of glutathione and the construction of genetically engineered microorganisms for producing glutathione.

The invention discloses a method for preparing butanediamine and spermidine by an enzyme method, and belongs to the field of bioengineering. The novel arginine decarboxylase mutant is successfully provided, the mutant shows excellent catalytic performance under the alkaline condition, and the specific enzyme activity of the mutant reaches 24.9 U / g and is improved by 8.3 times compared with that of wild type enzyme. The invention develops a two-step synthesis process based on the constructed arginine decarboxylase mutant, and the two-step synthesis process is used for efficiently preparing spermidine. Experimental results show that the process successfully realizes the remarkable increase of the yield of spermidine, and the final yield reaches 200.4 mg / L.

The invention provides a glutaminase mutant and application of the glutaminase mutant. Wherein the glutaminase mutant comprises (a) a protein which is subjected to amino acid mutation and has a glutaminase activity function on at least one of the following sites of S467, Y334, K400, N521, R337, E402 or D447 of an amino acid sequence as shown in SEQ ID NO: 2, and (b) a protein which is subjected to amino acid mutation on at least one of the following sites of S334, Y334, K400, N521, R337, E402 or D447 of the amino acid sequence as shown in SEQ ID NO: 2; and (b) a protein which has 80% or more homology with the amino acid sequence limited by (a) and has a glutaminase function. The glutaminase mutant with the amino acid sequence disclosed by the invention has relatively high specific enzyme activity during enzyme catalytic reaction, and is low in cost and strong in market competitiveness when being used for commercial food processing.

The invention discloses a microsphere entrapped with probiotics and ginsenoside as well as a preparation method and application of the microsphere, and aims to realize efficient treatment of flora imbalance inflammatory bowel disease (IBD). The microspheres adopt a bi-component synergistic entrapment technology, can stably bear probiotics and ginsenoside, effectively avoid inactivation or degradation of the probiotics and ginsenoside in gastric acid and cholate environments, and ensure directional release and efficient utilization of the probiotics and ginsenoside in intestinal tracts. The microspheres not only provide a protection effect as a delivery carrier, but also construct a'microreactor 'system, and provide a suitable microenvironment for survival of probiotics and conversion of ginsenoside. Probiotics secrete a specific enzyme to promote prototype ginsenoside to be converted into rare ginsenoside with higher activity and stronger solubility while regulating intestinal flora balance and relieving intestinal inflammation, so that the bioavailability and efficacy of the rare ginsenoside are remarkably improved. According to the microsphere system, the technical bottlenecks of the existing treatment means in the aspects of activity maintenance, directional release and conversion utilization are broken through by realizing the synergistic effect of the probiotics and the ginsenoside, and a brand-new strategy and a technical platform are provided for treatment of flora imbalance related diseases such as IBD.

The invention discloses a serine hydroxymethyltransferase mutant and an application thereof in production of L-serin.The serine hydroxymethyltransferase mutant with the specific enzyme activity remarkably improved is obtained by conducting saturated mutation on serine hydroxymethyltransferase from escherichia coli and conducting screening, and the serine hydroxymethyltransferase mutant is applied to synthesis of L-serine. The serine hydroxymethyltransferase disclosed by the invention can be used for effectively improving the efficiency of catalyzing glycine and formaldehyde to synthesize L-serine by using the serine hydroxymethyltransferase, reducing the enzyme dosage, remarkably reducing the production cost and reducing the separation difficulty of downstream products.

The invention relates to the field of nutritional health food, and discloses a casein modified active peptide for promoting bone repair and a preparation method thereof.The structure of the active peptide sequentially comprises a bone targeting sequence with high affinity to hydroxyapatite, a casein phosphopeptide core sequence capable of chelating calcium ions, a casein phosphopeptide core sequence capable of chelating calcium ions, a casein phosphopeptide core sequence capable of chelating calcium ions, a casein phosphopeptide core sequence capable of chelating calcium ions and a casein phosphopeptide core sequence capable of chelating calcium ions from the C-terminal to the N-terminal. The digestion sequence can be specifically hydrolyzed by matrix metalloproteinase, and the alkynyl functional group is used for covalent cross-linking. The active peptide can be mixed with an azido-containing multi-arm cross-linking agent, and hydrogel can be rapidly formed under physiological conditions through cycloaddition reaction. The system can be gelated in situ and anchored to a bone defect part in a targeted manner, and is triggered by a specific enzyme in a pathological microenvironment to controllably release active peptide fragments capable of chelating calcium ions, so that the concentration of local mineral ions is adjusted, the cell living environment is improved, and an effective new way is provided for promoting bone repair.

This invention discloses a mutant of raw starch hydrolase with improved stability and its applications. Using α-amylase AmyZ2 as the starting enzyme, and through computer-aided design to clarify the mutation site, a mutant was heterologously expressed in Bacillus subtilis, resulting in an α-amylase with improved stability. When using raw corn starch as a substrate, the mutant exhibits 1.57 times the specific enzyme activity and 2 times the stability of the starting enzyme. While maintaining the specific enzyme activity, the mutant enzyme shows a significant improvement in thermostability. This mutant has potential application value in the production of starch sugars using raw corn starch as a substrate.

The application discloses a D-allulose 3-epimerase mutant, a preparation method and application thereof, and relates to the fields of genetic engineering and enzyme engineering. The amino acid sequence of the D-allulose 3-epimerase mutant is shown as SEQ ID NO. 1. The specific enzyme activity of the D-allulose 3-epimerase mutant provided by the application is increased from 10.21 U / mg of a control (before mutation) to 15.29 U / mg at 80 DEG C and pH 6.0; and the equilibrium conversion rate is increased from 29.98% of the control (before mutation) to 36.26% when the substrate is 700 g / L of fructose. The D-allulose 3-epimerase mutant provided by the application has higher catalytic activity, and has a very broad application prospect in the efficient production and preparation of D-allulose.

The invention discloses an enzyme-containing anti-inflammatory composition for pet skin and hair follicle health. The enzyme-containing anti-inflammatory composition comprises an enzyme preparation, a hair follicle maintenance agent, a functional auxiliary agent and a carrier raw material. The core innovation lies in that a hair follicle targeted enzymolysis technology is adopted, and a specific enzyme modified by polyethylene glycol can efficiently dredge hair follicles; the anti-inflammatory and hair follicle repairing dual effects are achieved through anti-inflammatory-maintenance synergistic matching and adding sequence optimization; the damaged barrier is rapidly repaired by combining a composite barrier repairing agent and a gradient permeation process; enzyme activity and mildness are guaranteed by adopting a microcapsule embedding and low-temperature preparation technology. The composition can specifically solve the problems of hair follicle blockage, inflammation and unhairing, is suitable for pets of all ages and skin types, and is high in practicability.

The invention provides a method and a device for secondary filtration and re-removal of cholesterol ester after continuous blood purification and blood fat filtration, and belongs to the technical field of medical blood purification. According to the method and the device, the technology of combining enzymolysis, adsorption and membrane separation is adopted for residual CE in a CBP filtering product. The method comprises the following steps: firstly, decomposing CE into small molecules by using specific enzyme, and weakening the combination of CE and other components; residual impurities are further adsorbed through a high-performance adsorption material; and finally, efficient removal of CE is realized by virtue of a high-precision membrane separation technology, so that the residual quantity is reduced to be below a safety threshold value. Compared with a traditional technology, the problems that the CE-containing filtrate is high in recycling risk and low in resource utilization rate are effectively solved, the purity of a filtered product is remarkably improved, technical support is provided for industrial scenes such as plasma exchange, filtrate feedback, biopharmacy and extracorporeal circulation in the medical field, and the application prospect is wide. The safety and the resource utilization efficiency of the blood purification technology are promoted.

The application discloses a beta-1,4-xylanase mutant and a construction method thereof, and comprises the following steps: constructing a beta-1,4-xylanase recombinant expression vector; introducing the recombinant vector pNZ8048-P5-XynA into a competent lactococcus lactis by using an electrotransformation technology to construct a wild-type expression vector; on the basis, designing and constructing a multi-site mutant recombinant plasmid by using a site-directed mutation method, wherein the eighth asparagine (Asn) of the beta-1,4-xylanase is mutated into tyrosine (Tyr), the 22nd serine (Ser) is mutated into proline (Pro), and the 59th alanine (Ala) is mutated into lysine (Lys); introducing the multi-site mutant recombinant plasmid into the competent lactococcus lactis to construct a heterologous expression strain of the mutant beta-1,4-xylanase (Mut-1); and stably obtaining the mutant xylanase beta-1,4-xylanase (Mut-1) with high activity by using a metal affinity chromatography (Ni 2+ ) method. The specific enzyme activity of the mutant reaches 1929.30±5.36 U / mg, and the optimal temperature is increased by 15 DEG C compared with that of the wild type.

The invention discloses xylanase XynA00838, a truncated body of the xylanase XynA00838 for removing CBM1 and application of the xylanase XynA00838, and belongs to the technical field of microorganisms. The invention provides the XynA00838, the amino acid sequence of the truncation of the XynA00838 and the nucleotide sequence of the coding gene of the XynA00838, and provides characterization information, the XynA00838 and the truncation of the XynA00838 have obvious xylanase activity, and the specific enzyme activity of the truncation of the XynA00838 is obviously higher than that of wild type xylanase XynA00838 when six different plant polysaccharides are degraded, so that the XynA00838 and the truncation of the XynA00838 can be used for degrading various plant polysaccharides. When the truncated body degrades low-viscosity wheat arabinoxylan as a substrate, the specific enzyme activity reaches 4.46 + / -0.12 U / mg and is remarkably higher than that of wild type xylanase XynA00838. The CBM1 in the xylanase XynA00838 disclosed by the invention has a relatively good maintaining effect on the temperature stability of an enzyme catalysis module of the xylanase XynA00838. The truncated body XynA00838 delta CBM1 of the xylanase XynA00838 without the CBM1 has high enzyme activity and pH stability, so that the truncated body XynA00838 delta CBM1 has relatively great development and application potential, and a basic theoretical basis is provided for preparing a commercial feed enzyme preparation.

The invention discloses a glucose-6-phosphate dehydrogenase mutant as well as an expression strain and application thereof. According to the invention, on the basis of glucose-6-phosphate dehydrogenase from marine microorganisms, after a mutation site is selected by combining Evcouplings design with Fold X scoring, a recombinant plasmid is constructed, and a mutant gene is obtained. After the engineering bacteria containing the mutant plasmids are subjected to induced expression, the glucose-6-phosphate dehydrogenase G6PDH202-Des3 with improved specific enzyme activity is obtained. Under the condition of 37 DEG C, the specific enzyme activity of the mutant is improved to 1.6 times, and the stability is improved to 1.2 times. The mutant has potential application value in an in-vitro diagnostic kit for detecting creatine kinase activity by an enzyme method.

The application discloses a marine-derived cholesterol oxidase and a preparation method and application thereof, and relates to the technical field of biology. The amino acid sequence of the marine-derived cholesterol oxidase (SkChOx) is shown in SEQ ID NO. 1 or 3, the specific enzyme activity of the marine-derived cholesterol oxidase can reach 31.9 U / mg, the marine-derived cholesterol oxidase has excellent anti-reverse performance, maintains high stability in the pH range of 5.0-10.0, has good temperature tolerance, organic solvent tolerance and metal ion tolerance, and exhibits unique salt activation effect and salt tolerance. The enzyme is compounded with dithiothreitol (DTT) and nonylphenol polyoxyethylene ether (NP-40) to form a liquid enzyme preparation, and after incubation at 37 DEG C for 7 days under accelerated conditions, the catalytic activity of the liquid enzyme preparation still remains about 87%, the liquid enzyme preparation has excellent long-acting storage stability, and has wide application prospects in the fields of clinical diagnosis, food physical and chemical inspection, biosensor development and industrial preparation of steroid drugs.

The invention provides an N-deacetylase / N-sulfotransferase and an application of the N-deacetylase / N-sulfotransferase. According to the invention, systematic stability design and surface electrostatic optimization are carried out on the N-deacetylation structural domain of NDST, and multiple engineering strategies such as structural domain fusion and linker peptide optimization are combined to synergistically improve the specific activity, substrate affinity and bifunctional catalytic synergy of enzyme. Experimental results show that the specific enzyme activity of the modified NDST mutant is obviously higher than that of natural enzyme while the difunctional catalytic capability is maintained.

The invention relates to the technical field of biomedical detection, in particular to a multiple TMA-CRISPR detection kit aiming at respiratory pathogen RNA and application of the multiple TMA-CRISPR detection kit, and solves the problem of weak multiple detection sensitivity and signal recognition during CRISPR multiple detection.The multiple TMA-CRISPR detection kit is obtained by firstly screening specific TMA primers and crRNA of IAV, IBV, RSVA and RSVB; a TMA-CRISPR system containing a specific enzyme proportion and a buffer solution is optimized, TMA amplification and Cas12a2 side cutting activity are combined, the constructed multiple TMA-CRISPR kit can achieve 10 copy / microliter RNA detection within 40 minutes, a clinical detection result is highly consistent with qRT-PCR and is more sensitive, and the kit is suitable for rapid multiple diagnosis of respiratory pathogens.

The invention discloses an acyl-coenzyme A oxidase mutant as well as an expression strain and application thereof. On the basis of acyl coenzyme A oxidase derived from marine microorganisms, mutation sites are designed through Saprot and scored, and mutation is introduced through overlapping extension PCR (polymerase chain reaction), so that a mutant gene is obtained. After the engineering bacteria containing the mutant plasmids are subjected to induced expression, the acyl-coenzyme A oxidase with improved stability and specific enzyme activity is obtained. Under the condition of 37 DEG C, the stability of the mutant is improved by 1.3 times. When palmitoyl coenzyme A is used as a substrate, the specific enzyme activity of the mutant is improved to 1.5 times. The mutant has application value in an in-vitro diagnostic kit for detecting free fatty acid by an enzyme method.

The application discloses a basic xylanase mutant with improved specific enzyme activity and thermal stability and a preparation method thereof, and belongs to the field of genetic engineering and enzyme engineering. The application provides a basic xylanase mutant M22 through a semi-rational design method, wherein the specific enzyme activity of the mutant M22 is 211 U / mg, which is increased by 181.33% compared with that of a wild type. After 30 min of heat treatment at 75 DEG C, the residual activity of the mutant M22 relative to the wild type is 169.30%, and after treatment at 80 DEG C, 85 DEG C and 90 DEG C, the relative residual activities of the mutant M22 are 153.94%, 127.84% and 115.02% respectively relative to the wild type treated at 75 DEG C for 30 min. The basic xylanase mutant M22 obtained by the application has significantly improved specific enzyme activity and stability compared with the wild type, and has higher application value and potential in industrial production.

The invention is related to specific enzyme combinations for use in the field of the hair and scalp care products.

The invention relates to the technical field of gene engineering, and particularly discloses a chitinase truncated body, a recombinant expression vector thereof, and a construction method and application of engineering bacteria. The chitinase truncated body is Cq181NC, the amino acid sequence of the Cq181NC is as shown in SEQ ID NO: 1, and the nucleotide sequence for coding the chitinase is as shown in SEQ ID NO: 2. According to determination, the chitinase truncation provided by the invention has the advantages that the specific enzyme activity is obviously improved by 1.8 times compared with that of a wild type, the chitinase truncation is high in environmental change tolerance, and the thermal stability of the chitinase truncation is still 1.43 times that of the wild type (incubation is performed for 8 hours at 35 DEG C). More importantly, the spectrum of the enzymolysis product is changed: the wild type is mainly disaccharide and shows a typical excision enzyme mode; and the truncated Cq181NC generates a plurality of oligosaccharides including monosaccharide, disaccharide, trisaccharide and hexasaccharide, shows double catalytic characteristics of endonuclease and exonuclease, and has a better application prospect.

The present invention relates to detergents and cleaning compositions comprising an enzyme, an effective amount of a particular type of enzyme enhancer, such as an alkanediol having a carbon chain of 5 to 14 carbon atoms, glyceryl caprylate, 4-hydroxyacetophenone, ethylhexylglycerin, tropolone, or a mixture of the aforementioned enzyme enhancers, and a surfactant, as well as the use of the aforementioned detergents and cleaning compositions for preparing detergents and cleaning products for household, institutional and industrial applications. Furthermore, the present invention relates to a method for treating stained and / or soiled substrates using the enzyme detergents and cleaning compositions according to the present invention. In addition, the present invention relates to the use of certain substances, as defined herein, for enhancing the performance of enzymes in detergents and cleaning compositions and / or for improving the cleaning performance of detergents and cleaning compositions. Finally, the present invention relates to a method for enhancing the enzyme performance in detergents and cleaning compositions and / or improving the cleaning performance in detergents and cleaning compositions by adding an effective amount of a specific enzyme enhancer, for example, an alkanediol having a carbon chain of 5 to 14 carbon atoms, glyceryl caprylate, 4-hydroxyacetophenone, ethylhexylglycerin, tropolone, or a mixture of the aforementioned enzyme enhancers, to the aforementioned detergents and cleaning compositions.

The invention relates to a method for preparing fructo-oligosaccharide through enzymolysis and application of the fructo-oligosaccharide in special medical food, and belongs to the field of enzyme engineering. The preparation method comprises the steps of raw material pretreatment, step-by-step enzymolysis, enzyme deactivation, separation and purification and the like. The step-by-step enzymolysis is divided into three stages, specific enzymes are respectively added in each stage, and the temperature, the pH value, the stirring speed and the reaction time are accurately controlled. Compared with the traditional method, the method has the advantages of high conversion rate, low by-product, high reaction efficiency and the like. Besides, the experiment of applying the fructo-oligosaccharide prepared by the method to the tumor total nutrient formula food shows that the fructo-oligosaccharide can effectively improve the nutritional status of experimental animals, has an obvious synergistic effect when being used together with related products, and has a good application value in the field of special medical foods.

The application discloses a method for preparing putrescine and spermidine by using an enzyme, and belongs to the field of bioengineering.The application successfully provides a novel arginine decarboxylase mutant, the mutant exhibits excellent catalytic performance under alkaline conditions, and the specific enzyme activity reaches 24.9 U / g, which is 8.3 times higher than that of a wild-type enzyme.Based on the constructed arginine decarboxylase mutant, the application develops a two-step synthesis process for efficiently preparing spermidine.The experimental results show that the process successfully realizes significant improvement of the yield of spermidine, and the final yield reaches 200.4 mg / L.

This invention discloses a mutant of Mycobacterium tuberculosis tyrosine lyase and its applications, belonging to the fields of molecular biology and biocatalysis. This mutant, denoted as mutant I384V, is obtained by mutating isoleucine at position 384 of the Mycobacterium tuberculosis tyrosine lyase to valine. I384V has similar optimal temperature and pH to the wild-type tyrosine lyase, but exhibits higher specific enzyme activity and catalytic efficiency. Compared to the wild-type, the mutant I384V improves the synthesis efficiency of levodopa by 38.4%, showing broad prospects for large-scale industrial application.

The invention provides an alcohol dehydrogenase mutant as well as a recombinant expression plasmid, a recombinant genetically engineered bacterium and application thereof. The amino acid sequence of the alcohol dehydrogenase mutant is as shown in SEQ ID NO.3, 5 or 7 in a sequence table, and the alcohol dehydrogenase mutant is an alcohol dehydrogenase directional modified enzyme which is obtained by a directional mutation technology and has higher specific enzyme activity; the recombinant expression plasmid contains the alcohol dehydrogenase mutant; the recombinant genetically engineered bacterium is constructed from recombinant expression plasmids and is used for catalyzing 5-hydroxyvaleraldehyde to generate 1, 5-pentanediol, the concentration of 1, 5-pentanediol is remarkably increased under the same reaction condition, and the recombinant genetically engineered bacterium has a huge industrial application prospect.