914 results about "Cystine" patented technology

The invention discloses a fatty acid modified coronavirus antigen and application thereof, and belongs to the field of biological medicine. The fatty acid modified coronavirus antigen contains fatty acid modified N-terminal cysteine (Cys) and a coronavirus antigen, and can contain a connecting structural domain; the coronavirus antigen is a coronavirus spike protein (S protein) receptor binding domain (RBD). The fatty acid modified coronavirus S protein RBD can be self-polymerized into nanoparticles, and compared with the RBD which is not subjected to fatty acid modification, the antigen can induce faster and higher humoral immunity through injection immunity, can induce mucosal immunity and humoral immunity through respiratory tract atomization immunity, and is a candidate mucosal vaccine with potential medical value.

The invention belongs to the field of bioengineering, and particularly discloses a tryptophan synthetase mutant with improved enzymatic activity and application of the tryptophan synthetase mutant in production of L-cysteine. Compared with wild tryptophan synthetase from escherichia coli, the amino acid sequence of the tryptophan synthetase mutant has the advantages that a beta catalytic subunit has T69A, S143A, R219E and F280H site combined mutation. Researches show that the enzyme activity of the mutant is increased by 2.4 times compared with that of a wild type through enzyme activity determination and analysis of inducible expression and purification. The beneficial tryptophan synthetase mutant provided by the invention can efficiently biocatalyze L-serine and sodium hydrosulfide to synthesize L-cysteine, and has a better industrial application prospect.

The invention provides a porcine oocyte in-vitro maturation culture solution additive and application thereof, and belongs to the field of embryo engineering, and the additive contains taurine. The additive also contains sodium pyruvate, cysteine, glucose, NaHCO3, fetal calf serum, estradiol, pregnant horse serum gonadotropin and human chorionic gonadotropin. When the porcine oocyte in-vitro maturation culture solution added with the additive is used for culturing porcine oocytes in vitro, the ROS content in the porcine oocytes can be remarkably reduced, the oxidation resistance of the porcine oocytes can be improved, and the mitochondrial distribution of the oocytes can be improved, so that the development of the oocytes can be improved; the maturation of porcine oocytes and the development of early embryos are promoted. When the technology is applied to the pig assisted reproduction technology, the success rate and quality of embryo engineering can be improved; the pig oocyte in-vitro maturation culture solution added with the additive can improve the premature embryo division rate in parthenogenetic activation of the pig oocytes.

The invention relates to the technical field of microbial genetic engineering, in particular to a method for improving cordycepin synthesized by saccharomyces cerevisiae and saccharomyces cerevisiae engineering bacteria. According to the invention, codon-optimized 2 '-carbonyl-3'-deoxyadenosine reductase gene and 3 '-adenosine monophosphate phosphohydrolase gene from cordyceps militaris are expressed by using plasmids, and then the plasmids are transformed into host cells to obtain the saccharomyces cerevisiae engineering bacteria. And inoculating a seed solution obtained by seed culture of the activated saccharomyces cerevisiae engineering bacteria into a fermentation culture medium containing a metabolic effector, and carrying out fermentation culture to synthesize cordycepin. Metabolic effectors (Cu < 2 + >, Fe < 2 + >, Mg < 2 + >, Zn < 2 + >, citric acid, cysteine, aspartic acid, glycine, VB1 and tea polyphenol) are added into a fermentation culture medium strain, and the variety and concentration of the metabolic effectors are optimized, so that the yield and synthesis efficiency of cordycepin are remarkably improved. By using the combination of the strain obtained by the invention and the optimal effector, the yield of cordycepin in a fermentation tank reaches 2.9 g / L.

The invention relates to a culture solution for recovering the quality of porcine oocytes by adding uridine. The culture solution comprises a basic culture solution and uridine, the basic culture solution contains 10% of pig follicular fluid, 0.57 mM of cysteine, 0.5 IU / mL of LH, 0.5 IU / mL of FSH, 10 ng / mL of epidermal growth factors, 1% of a double-antibody TCM 199 culture medium and the balance of water; the addition amount of uridine is 100 [mu] M of the basic culture solution. According to the method disclosed by the invention, metabolite uridine (Urd) required by a human body is used for respectively rescuing in-vitro cultured H2O2 induced oxidative stress porcine oocytes and delayed cultured aged porcine oocytes, so that the quality of the oocytes is improved.

The invention relates to the technical field of biology, in particular to a method for synthesizing S-sulfo-L-cysteine through multi-enzyme cascade catalysis. The invention provides a new route for biosynthesis of S-sulfo-L-cysteine, and a test result shows that serine, AMP, sodium hexametaphosphate and sodium thiosulfate are used as substrates, and the S-sulfo-L-cysteine is synthesized by a one-step method. A crude enzyme liquid which contains serine kinase, polyphosphoric acid-AMP phosphotransferase and phosphoserine dependent type S-sulfo-L-cysteine synthetase in which the background of tryptophanase and glutaredoxin cells is knocked out is used for synthesizing the S-sulfo-L-cysteine, the steps are simple, the product yield is high, the cost is low, and the method has a relatively strong industrial application prospect.

The invention relates to the technical field of biology, and discloses a carbonyl reductase mutant and application thereof in enzymatic synthesis of chiral alcohol. The amino acid sequence as shown in SEQ ID NO.2 is subjected to mutation that 36th lysine is mutated into any one of aspartic acid, threonine and valine, or / and 125th histidine is mutated into any one of lysine, serine and leucine, or 170th histidine is mutated into any one of lysine, cysteine and leucine. The carbonyl reductase mutants, especially single-site mutants Mut-T75K, Mut-T75D and Mut-E216M and a combined mutant Mut-T75K-E216M, with activity improved to different extents compared with that of a wild type are obtained, have excellent relative enzyme activity, thermal stability and substrate tolerance, have relatively high activity and stability for various chiral alcohols, and can be used for preparing the carbonyl reductase mutants. The catalyst has the advantages of high catalytic activity, high thermal stability, strong substrate tolerance, easiness in fermentation and the like.

The invention relates to a plasma metabolite composition for auxiliary diagnosis of sub-clinical mastitis of dairy cows and application of the plasma metabolite composition. The plasma metabolite combination is a first combination and / or a second combination, and the first combination is composed of glyceryl monolinoleate, 2-methylthiophene, L-cystine, (S)-(+)-citramalic acid, 9-hydroxy-10, 12-octadecadienoic acid, 16-hydroxyhexadecanoic acid, tyrosine hydroxyproline, stearoyl serotonin and histamine; the first composition is composed of 4, 5-dimethyl-2, 4, 5-trimethyloxazole, 12, 13-epoxy octadecadienoic acid, 2-cyclotetradecene-1-ketone, 4 [alpha]-carboxyl-5 [alpha]-cholest-8-ene-3 [beta]-alcohol, N-arachidonyl dopamine d8, 9 (Z) and 11 (E)-conjugated linoleic acid, and the second composition is composed of 2, 5-dihydro-2, 4, 5-trimethyloxazole, 12, 13-epoxy octadecadienoic acid, 2-cyclotetradecene-1-ketone, 4 [alpha]-carboxyl-5 [alpha]-cholest-8-ene-3 [beta]-alcohol, N-arachidonyl dopamine A product prepared based on the plasma metabolite composition and used for auxiliary diagnosis of cow subclinical mastitis is simple in use method and high in accuracy, can be used for assisting a milk somatic cell number method to diagnose cow subclinical mastitis, and reduces the probability of false negative and false positive.

The invention provides pantoea agglomerans and application thereof, and belongs to the technical field of microorganisms, the strain is preserved in China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC No.36122; the strain has very high selenium tolerance and transformation capacity, and can transform inorganic selenium (such as Se (IV)) with relatively high toxicity into organic selenium (such as selenomethionine and selenocystine) with low toxicity and zero-valent nano-selenium (Se0) in a culture medium containing sodium selenite. The pantoea agglomerans obtained by the invention has the characteristics of selenium-addictive microorganisms, and has potential application value in biotransformation of selenium, microbial synthesis of nano-selenium, and growth promotion and selenium enrichment of crops. The pantoea agglomerans can promote plant growth, a liquid fermentation process developed by the strain is utilized, the highest conversion rate of organic selenium can reach 92.5%, and the synthesis efficiency of nano-selenium reaches 88.3%. And development of organic selenium agricultural products is well facilitated.

The invention provides an oxygen-carrying protein molecule and a preparation method and application thereof, and relates to the technical field of functional protein preparation, the oxygen-carrying protein molecule comprises at least one cysteine part and at least one histidine part, the cysteine part comprises acetyl or ethyl maleoyl, and the histidine part comprises histidine. The histidine moiety includes a benzimidazole derivative group. The benzimidazole derivative is adopted as an auxiliary molecule and participates in the modification process of the sulfydryl modified compound on the hemoglobin, the modification site selectivity is improved, the conformational change is reduced, and the modification degree is accurately controlled, so that the oxygen binding force P50 of the modified hemoglobin is effectively improved.

The invention belongs to the technical field of preparation of fluorescent powder, and particularly relates to double-shell narrow-band red-light fluorescent powder as well as a preparation method and application thereof. The narrow-band red-light fluorescent powder is Mn < 4 + >-doped potassium fluosilicate fluorescent powder, and the narrow-band red-light fluorescent powder is coated with a potassium fluosilicate inner shell layer and a cystine outer shell layer. The preparation method comprises the following steps: mixing a cysteine solution with the narrow-band red-light fluorescent powder, stirring, centrifuging, and drying the precipitate obtained by centrifuging to obtain the double-shell narrow-band red-light fluorescent powder. The surface of the prepared fluorescent powder is provided with the Mn < 4 + >-free potassium fluosilicate inner shell layer and the outer hydrophobic cystine layer, the surface of the core narrow-band red-light fluorescent powder is covered with the double-shell structure, the water resistance and the light-emitting characteristic of the narrow-band red-light fluorescent powder can be remarkably improved, and the wide application prospect is achieved.

The invention relates to a carbon dioxide electrocatalytic reduction catalyst, in particular to an L-cysteine modified nano-silver electrocatalyst and application thereof, and belongs to the technical field of carbon dioxide emission reduction and resource utilization and electrocatalytic material synthesis. A preparation method of the L-cysteine modified nano-silver electrocatalyst comprises the following steps: S1, dissolving silver nitrate in water to obtain a 0.05-100mM silver nitrate solution, adding the silver nitrate solution into ethylene glycol, and uniformly stirring; the volume ratio of the silver nitrate solution to the ethylene glycol is 1: (2-20); s2, L-cysteine is added into the mixed solution, microwave heating is performed after uniform stirring, obtained solids are centrifugally washed at least three times with ethyl alcohol and ultrapure water respectively, and the solids are dried in a vacuum drying box to obtain nano-silver particles; the molar ratio of the silver element to the L-cysteine is 1: (0.01-10). By improving the adsorption capacity of the electrocatalyst on active substances, high selectivity and high stability of the product CO in a CO2 in-situ conversion system are realized.

The invention provides a drug permeability clinical prediction model, a construction method thereof and a non-specific drug permeability evaluation method, and belongs to the technical field of biological medicine. The invention provides a construction method of a drug permeability clinical prediction model. According to the construction method, intestinal microorganism characteristics are introduced into model construction for the first time. The prediction performance of the constructed LGBM model containing the intestinal microorganism characteristics in the aspect of NAC permeability prediction is superior to that of other traditional business models. The invention also provides a serine-derived sphingolipid de novo synthesis pathway, which is different from the traditional sphingolipid de novo synthesis pathway, and is named as a cysteine sphingolipid metabolism pathway, NAC-derived cysteine may participate in the biosynthesis of microbial sphingolipid through covalent binding with palmitoyl-CoA, thereby damaging intestinal permeation of NAC.

The present invention relates to: a temperature-sensitive hydrogel for cancer treatment; a photothermal composition comprising the hydrogel as an active ingredient; and a preparation method for the temperature-sensitive hydrogel for cancer treatment. The temperature-sensitive hydrogel of the present invention includes gold nanostars as active ingredients, and thus can generate heat by light irradiation, thereby exhibiting a photothermal therapy effect. In addition, the hydrogel temperature increases so that the release of nitric oxide (NO) from S-nitrosocysteine can be induced. In addition, the temperature-sensitive hydrogel of the present invention includes S-nitrosocysteine as an active ingredient so that, upon a temperature rise due to a photothermal reaction, the penetration of drugs into a tumor site can be improved by the release of NO, and at the same time, apoptosis of cancer cells can be directly caused; and includes an immunotherapy agent as an active ingredient so that tumor size can be effectively suppressed even with the passage of time. Therefore, as a material that enables complex treatment combined with photothermal therapy and immunotherapy, the temperature-sensitive hydrogel of the present invention having the aforementioned effect can be usefully utilized in the field of medicine for cancer treatment.

The invention provides application of a metabolite S-cysteine succinic acid (S-Cysteinosuccinic acid) as a molecular marker for diagnosis and prognosis of lung cancer brain metastasis tumors, and application of a reagent for detecting the metabolite in preparation of a reagent for diagnosis and prognosis of the lung cancer brain metastasis tumors. The invention further provides a method for evaluating the occurrence risk of the lung cancer brain metastasis tumor, and the method comprises the steps that subjects are divided into a high-risk group of the lung cancer brain metastasis tumor and a low-risk group of the lung cancer brain metastasis tumor according to the expression level of metabolites in samples of the subjects, and the metabolites comprise S-Cysteinosuccinic acid. The invention also relates to a kit or a chip containing the reagent for detecting the metabolite.

The invention discloses a polypeptide with a whitening effect and a preparation method and application thereof.The polypeptide is obtained from hydrolyzed protein of babylonia areolata, the amino acid sequence of the polypeptide is cysteine-arginine-proline-threonine-cysteine-serine-arginine-leucine-alanine-cysteine, and the amino acid sequence of the polypeptide is cysteine-arginine-proline-threonine-cysteine-serine-arginine-leucine-alanine. The compound can obviously inhibit the generation of melanin in cells and the activity of tyrosinase in vitro, has the characteristics of low toxicity, low irritation, good stability, safety and high efficiency, and can be applied to whitening cosmetics.

The invention relates to the technical field of flocculants, and discloses a flocculant capable of degrading sewage and a preparation method of the flocculant, thiourea, sulfydryl and other groups in an alkenyl thiourea cysteine monomer have excellent adsorption and chelation effects on heavy metal ions, and stable complexes and chelate precipitates can be formed, so that heavy metals are removed from wastewater; sulfydryl and carboxyl in the structure are easily soluble in water, so that the solubility of chitosan is improved, and the coordination capability is improved; the positively charged quaternary ammonium salt cations in the flocculant can adsorb more kaolin particles and neutralize charges on the surfaces of the particles to generate an adsorption bridging effect, and can influence substance energy exchange and normal metabolism of bacterial cell membranes at the same time, so that bacteria are inhibited or killed, and a sterilization effect is achieved; the prepared flocculant still has a good flocculation effect on heavy metal ions after being desorbed and recycled for multiple times, can be recycled, and is non-toxic, harmless and biodegradable.

The invention discloses a method for efficiently producing ergothioneine by metabolic engineering modified escherichia coli and application, and belongs to the technical field of biology. By adopting the recombinant escherichia coli EGT-1-B * provided by the invention, glucose can be converted into ergothioneine; therefore, the raw materials are cheap and easy to obtain, additives and heavy metals which are harmful to human health are avoided, a good foundation is laid for later product purification, and the requirements of commercial application can be met. Furthermore, genes related to metabolism of histidine, methionine, cysteine and S-adenosylmethionine are further overexpressed in the recombinant escherichia coli EGT-1-B *, so that the content of precursor amino acid synthesized by the ergothioneine is increased, and meanwhile, after the gene yqaB is knocked out, the yield of the ergothioneine is further increased; the utilization rate of glucose to ergothioneine can be further improved, and the yield of ergothioneine can reach 140.29 mg / L.

The invention discloses a gelator and a preparation method and application thereof, the structural formula of the gelator is # imgabs0 #, R1 is a side chain group connected to an amino acid central carbon atom except an amino group, a carboxyl group and a hydrogen atom; the amino acid is selected from one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, selenocysteine and pyrrole lysine; the amino acid is selected from one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, selenocysteine and pyrrole lysine; r2 is alkyl with the carbon atom number of 16 to 19; and R3 is 9-fluorenyl methoxy carbonyl group or t-butyloxycarbonyl group. The gelator has a hydrophobic long alkyl tail chain, can spontaneously gather and assemble into a three-dimensional network structure through hydrogen bonds, pi-pi interaction and hydrophobic force, and fixes an oil phase in an oil solvent or an oil-water mixture in an effective manner to form high-strength gel.

The invention includes compositions comprising at least one chimeric autoantibody receptor (CAAR) specific for an anti-phospholipase A2 receptor (PLA2R) autoantibody-based B cell receptor (BCR), polynucleotides encoding the CAAR, vectors comprising a polynucleotide encoding the CAAR, and recombinant cells (e.g., T cells) comprising the CAAR, wherein the CAAR comprises a PLA2R autoantigen comprising an extended cysteine rich (eCysR) domain comprising (a) a PLA2R N-terminal peptide and a cysteine rich (CysR) domain, and (b) a C-type lectin domain 7 (CTLD7). The invention also includes methods of making a genetically modified cell, e.g., a genetically modified T cell, expressing a PLA2R-CAAR wherein the expressed CAAR comprises a PLA2R autoantigen comprising an extended cysteine rich (eCysR) domain comprising (a) a PLA2R N-terminal peptide and a cysteine rich (CysR) domain, and (b) a C-type lectin domain 7 (CTLD7).

The invention discloses a bran fermented biological feed and a preparation method thereof, and belongs to the technical field of feeds. The bran fermented biological feed is prepared by uniformly mixing and fermenting the following raw materials: wheat bran, corn flour, soybean meal, calcium hydrogen phosphate, sodium chloride, an enzyme preparation, a water retention setting agent, a mildew preventive and water, wherein the enzyme preparation is prepared from lactobacillus plantarum, bacillus subtilis and saccharomycetes; the mildew preventive is prepared by the following steps: reacting chitosan oligosaccharide with propiolic acid to obtain modified chitosan oligosaccharide, reacting L-cystine with ethyl azidoacetate to obtain an azide compound, and finally reacting the modified chitosan oligosaccharide with the azide compound. The prepared bran fermented biological feed has an excellent mildew-proof effect and a low pulverization rate, and storage and transportation of the feed are facilitated.

The invention relates to the technical field of plant polysaccharide extraction, in particular to a plant polysaccharide extraction method and plant polysaccharides, and the extraction method comprises the following steps: carrying out wall breaking treatment on edible mushrooms to obtain wall-broken edible mushroom powder; mixing the edible mushroom powder with an L-cysteine solution according to a solid-liquid ratio of 1g: (10-20) mL to obtain a wall-broken edible mushroom powder solution; adding a plant compound enzyme into the wall-broken edible fungus powder solution, adjusting the pH value to 4.5, heating to 40 DEG C, performing enzymolysis for 1.5-2 hours under the stimulation action of a micro direct-current electric field, and performing enzyme deactivation to obtain a plant polysaccharide crude extract; and deproteinizing the plant polysaccharide extracting solution by using a Sevag method, carrying out alcohol precipitation separation, concentrating and drying to obtain the polysaccharide extract. According to the method disclosed by the invention, an enzymolysis mode under the stimulation of a micro direct-current electric field is adopted, and an L-cysteine solution oscillation soaking mode is combined, so that the extraction rate of the plant polysaccharide can be remarkably improved, and the activity of the plant polysaccharide is ensured.

Pharmacological compound for stimulation of the follicular unit. The pharmacological compound is for the stimulation of the follicular unit. The pharmaceutical compound has fisnasteride, minoxidil, cystine, methionine, astaxanthin, melatonin, biotin, retinol, iron, selenium, collagen, zinc, molybdenum and vitamin D.

The invention provides a method for simultaneously detecting at least two of cysteine, acetylcysteine and cystine or salts of amino acids in an amino acid composition. High performance liquid chromatography is adopted for detection, and chromatographic conditions comprise that octadecylsilane chemically bonded silica is adopted as a chromatographic column of a filler, and a mobile phase A and a mobile phase B are adopted for gradient elution; wherein the mobile phase A is a mixed solution of an ammonium sulfate solution and an ion pair reagent. According to the method disclosed by the invention, cysteine, acetylcysteine, cystine or salts of the amino acids in the amino acid composition can be separated from one another and can be effectively separated from other amino acid components or impurities, and the separation degree is high; cysteine, cystine and acetylcysteine in the reference substance and amino acid composition are stable in retention time and good in peak shape. The method provided by the invention has the advantages of strong specificity, good stability, high accuracy, accurate, reliable and effective detection result, good repeatability and high precision.

The mixture as the micronutrient composition is a combination of alpha-ketoglutaric acid, nicotinamide or nicotinic acid, L-proline, L-glutamine, L-citrulline, sodium pyruvate, pantothenic acid, L-cysteine or N-acetylcysteine, magnesium malate, magnesium citrate, and methionine. The mixture is effective for the treatment of diseases due to oxidative stress. More specifically, the mixtures and cores as micronutrient compositions are effective in reversing saccharification in diabetes mellitus.

The invention discloses a method for detecting L-cysteine in serum based on N, S co-doped carbon nanodots, and belongs to the field of analysis and detection. The method comprises the following steps: (1) preparing carbon dots by taking beta-mercaptoethylamine and p-phenylenediamine as precursors; (2) after Fe < 3 + > is added into the carbon dot solution, a carbon dot fluorescence quenching phenomenon occurs, and a carbon dot-Fe < 3 + > mixed system is obtained; then adding L-cysteine into the carbon dot-Fe < 3 + > mixed system to gradually recover the fluorescence of the system; and (3) constructing a linear relationship between the concentration of the L-cysteine and the fluorescence recovery degree to obtain the quantitative detection model for the L-cysteine in the serum sample. According to the method, the carbon dots are prepared by taking beta-mercaptoethylamine and p-phenylenediamine as precursors for the first time, quantitative detection of L-cysteine is realized, and the method is low in cost, high in sensitivity, suitable for field rapid detection and relatively high in practical value and popularization prospect.

The invention relates to a preparation method of a high-temperature proton exchange membrane, in particular to a preparation method of a phosphoric acid / cystine functionalized MXene / polybenzimidazole composite high-temperature proton exchange membrane for a high-temperature fuel cell. The invention aims to solve the problem of insufficient oxidation resistance of the existing fuel cell proton exchange membrane. The method comprises the following steps: 1, preparing polybenzimidazole; (2) preparing cystine functionalized MXene; and 3, preparing a cystine functionalized MXenen and OPBI compounded proton exchange membrane, and then dipping in a phosphoric acid solution. According to the application of the cystine functionalized MXene / polybenzimidazole composite membrane for the high-temperature fuel cell in HT-PEM, the conductivity and oxidation resistance of a proton exchange membrane are improved, a basis is provided for developing novel efficient HT-PEM, and the cystine functionalized MXene / polybenzimidazole composite membrane is applied to the technical field of proton exchange membrane fuel cells.

The present invention discloses a method for constructing a Clostridium butyricum / CdS hybrid system and its application, which mainly comprises the following steps: (1) culturing microorganisms: culturing Clostridium butyricum at 37°C using a TGY culture medium to obtain a fresh Clostridium butyricum bacterial liquid; (2) constructing a Clostridium butyricum / CdS composite system: adding L-cysteine ​​hydrochloride and CdS to the bacterial liquid; 2+ Metal ions in situ form nanoparticles CdS and self-assemble on the surface of Clostridium butyricum cells; under light irradiation, the concentration of NADH in the Clostridium butyricum / CdS system is detected to evaluate the photocatalytic performance of the system. Starting from the current energy shortage problem, the present invention utilizes the renewable solar energy in nature to construct a photosynthetic biological hybrid system that combines the advantages of semiconductor light-harvesting ability and microbial metabolic catalytic ability, and can be applied to microorganisms to efficiently produce high value-added products such as butyric acid, H2, ethanol, 1,3-propylene glycol, etc.

The invention relates to the technical field of biology, and discloses a recombinant carbonyl reductase mutant and application thereof in synthesis of chiral alcohol. According to the invention, the 36th-site lysine is mutated into any one of aspartic acid, threonine and valine, or / and the 125th-site histidine is mutated into any one of lysine, serine and leucine, or / and the 170th-site histidine is mutated into any one of lysine, cysteine and leucine; the carbonyl reductase mutants, especially single-site mutants Mut-K36D and Mut-H125K and a combined mutant Mut-K36D-H125K, with activity improved to different extents compared with that of a wild type are obtained, have excellent thermal stability and relative enzyme activity, have relatively high activity and stability aiming at various chiral alcohols, and can be used for preparing the carbonyl reductase. The method has the advantages of high catalytic activity, high enzyme expression quantity, easiness in fermentation and the like.

The invention provides a high-yield L-cysteine engineering bacterium accumulated by sulfur donor 3 '-phosphoadenosine-5'-phosphoryl sulfuric acid as well as a construction method and application of the high-yield L-cysteine engineering bacterium. According to the method, the copy number of key genes in a cysteine synthesis route in an escherichia coli organism is changed, heterologous genes are introduced, the expression level of the key genes in the cysteine synthesis route in the escherichia coli organism is enhanced, and sulfur flux is further made to flow to synthesis of L-cysteine. On the basis that the chassis bacteria enhance the carbon flux, in order to maintain the balance of carbon and sulfur in the strain and continuously enhance the synthesis of the sulfur flux flowing to the L-cysteine, the synthesis of the product is promoted by enhancing the synthesis capability of a sulfur donor PAPS in a sulfate pathway, and finally, the plasmid-free and antibiotic-free engineering strain for high yield of the L-cysteine is obtained. Finally, the shake flask titer of the L-cysteine reaches 6.06 g / L and is increased by 49.2% compared with that of an original strain.