2188 results about "Lysine" patented technology

Aspects of the disclosure relate to compositions comprising a plurality of complexes comprising an antibody (e.g., anti-TfRI antibody) covalently linked to one or more oligonucleotides (e.g. a DMPK targeting oligonucleotide), each oligonucleotide being covalently linked at a linkage site represented by a lysine (K) residue of the antibody. In some embodiments, the antibody comprises a heavy chain comprising a heavy chain variable region (VH) and a heavy chain constant region, and a light chain comprising a light chain variable region (VL) and a light chain constant region, wherein at least 80% (e.g., 80%-98%, 80%-95%, 80%-90%, 85%-98%, 85%-95%, 85%-90%, 90%-98%, 90%-95%, 95%-97%, or more) of the light chain constant regions of the antibodies of the complexes in the composition are independently covalently linked to an oligonucleotide at a linkage site represented by K188 (based on Kabat numbering) and / or a linkage site represented by K190 (based on Kabat numbering) of the light chain constant regions of the antibodies.

The invention belongs to the technical field of protein engineering, and discloses a Brazilian sweet protein mutant and application thereof. According to the invention, lysine is used for replacing aspartic acid at the 29th site of Brazilian sweet protein, and / or arginine is used for replacing glutamic acid at the 36th site, and / or alanine is used for replacing aspartic acid at the 50th site, amino acid mutation at the sites is carried out to construct a Brazilian sweet protein mutant, and the Brazilian sweet protein mutant is subjected to heterologous expression in pichia pastoris GS115, so that the Brazilian sweet protein mutant is obtained. And carrying out sweetness performance evaluation on the expressed Brazilian sweet protein mutant. The sweetness property of the double mutant Asp29Lys-Asp50Ala protein is improved by 240% compared with the sweetness property of the Brazilian sweet protein before mutation.

The invention discloses an antibacterial nylon material as well as a preparation method and application thereof, relates to the technical field of antibacterial high polymer materials, and solves the problems of poor antibacterial performance and difficulty in industrial production of existing antibacterial nylon 6. The preparation method comprises the following steps: mixing a seven-membered cyclic lysine derivative monomer with lactam, and carrying out hydrolytic polymerization by taking water as an initiator to obtain copolyamide; and placing the copolyamide in an acid solution, heating and stirring to carry out protonation reaction, and purifying the reaction product to obtain the antibacterial nylon material. The seven-membered cyclic lysine derivative monomer is an unprotected cyclic lysine monomer (aminocaprolactam), a single protected cyclic lysine monomer or a salified cyclic lysine monomer. The method can be widely applied to the fields with antibacterial requirements, such as fabrics, plates, pipes, packaging and various panels.

The invention discloses a high-performance carbonyl reductase mutant and application thereof in synthesis of a series of chiral alcohols. The high-performance carbonyl reductase mutant is obtained by performing the following mutations on an amino acid sequence as shown in SEQ ID NO.2: the 69th alanine mutates into any one of lysine, leucine, aspartic acid or asparagine, and the 69th alanine mutates into any one of lysine, leucine, aspartic acid or asparagine; and / or the 100th glycine is mutated into any one of glutamic acid, serine, lysine or asparagine. Compared with a wild type enzyme, the thermal stability and the catalytic activity of the obtained mutant are remarkably improved, particularly, single point mutants Mut-A69N, Mut-G100E and Mut-G100N and a combined mutant Mut-A69N-G100N show excellent relative enzyme activity, thermal stability and substrate tolerance. The mutant has high catalytic activity and stability to various chiral alcohols, and the contradiction that the traditional carbonyl reductase is easy to inactivate at high temperature and the catalytic efficiency is difficult to achieve at the same time is solved. The invention provides an efficient and stable enzyme catalysis tool for green biological preparation of chiral drug intermediates.

The invention discloses a ruminant feed capable of replacing soybean meal as well as a preparation method and application of the ruminant feed. The ruminant animal feed is prepared from the following raw material matrixes in parts by weight through compound probiotic fermentation: 45-55 parts of corn sugar residues, 15-25 parts of corn steep liquor, 10-20 parts of corn germ meal, 3-8 parts of extruded soybeans, 3-8 parts of corn protein powder, 2-4 parts of urea and 0.5-1.5 parts of lysine. The compound probiotics are prepared from saccharomyces cerevisiae, lactobacillus plantarum and bacillus subtilis. The invention further discloses a preparation method of the ruminant feed and application of the ruminant feed in completely replacing soybean meal in daily ration of ruminants. The ruminant feed disclosed by the invention can completely replace soybean meal in daily ration of ruminants, and even if the ruminants are in a fattening period, the soybean meal does not need to be additionally added to maintain protein supply, so that the feed cost is effectively reduced, and multiple targets of saving cost, improving efficiency and protecting environment are achieved.

The invention discloses functional caprolactam, an intrinsic flame-retardant nylon material as well as a preparation method and application thereof, and relates to the technical field of flame-retardant nylon materials. The preparation method comprises the following steps: preparing an alpha-amino-epsilon-caprolactam intermediate by taking lysine as an initial raw material through one-step efficient cyclization, then reacting with a reagent containing a flame-retardant group to obtain functional caprolactam, and finally introducing the flame-retardant group into a side chain of nylon 6 by utilizing ring-opening copolymerization of the functional caprolactam and caprolactam to prepare the intrinsic flame-retardant nylon material. The flame-retardant nylon material can effectively avoid the migration and loss of the flame retardant, improve the dispersity of the flame retardant and enhance the flame-retardant effect, can keep the main chain structure of the nylon 6 unchanged, reduces the influence on the inherent performance of the nylon 6, is expected to directly replace the existing nylon 6 material, and is applied to the fields of automobiles, textiles, electronics and electrics, buildings, packaging and the like. In addition, a renewable lysine resource is used for partially replacing a petroleum resource, so that the method has the advantages of resource conservation, environmental friendliness, simple process, low cost and the like.

The invention discloses a flame-retardant nylon material as well as a preparation method and application thereof, relates to the technical field of flame-retardant high polymer materials, and solves the problems that a flame-retardant nylon material prepared by a blending method is unstable in flame-retardant effect and a flame-retardant nylon material prepared by a copolymerization method is complex in process. The preparation method comprises the following steps: carrying out ring-opening copolymerization on a seven-membered ring lysine derivative monomer formed by ring formation of lysine and other lactam monomers to obtain copolyamide with a functional group on a side chain, and reacting a reagent containing a flame-retardant group with the functional group to prepare the flame-retardant nylon material. The flame-retardant nylon material prepared by the invention can effectively avoid migration and loss of the flame retardant, improve the dispersity of the flame retardant and enhance the flame-retardant effect. Meanwhile, a renewable lysine resource is used for partially replacing a petroleum resource, so that the method has the advantages of resource conservation, environmental friendliness, simple process, low production cost and the like. The flame-retardant nylon material disclosed by the invention has lasting and stable flame-retardant performance and can be widely applied to the fields of automobiles, textiles, electronics and electricity, buildings, packaging and the like.

The invention discloses a high-efficiency lysine decarboxylase mutant and an application of the high-efficiency lysine decarboxylase mutant in synthesis of pentamethylene diamine. A series of mutants including a single mutant (such as N218G, T222V, C244P and the like), a double mutant and a three mutant are obtained by carrying out multi-site mutation on wild type lysine decarboxylase (SEQ ID NO.2) from Klebsiella grimontii. The catalytic efficiency of the mutant is remarkably improved, and the activity of the mutant is improved by 5.0-10.2 times compared with that of a wild type enzyme. According to the method disclosed by the invention, the substrate conversion rate of 99% or above can be realized within 2 hours through an optimized process of constructing an expression vector and a genetically engineered bacterium, inducing expression of lysine decarboxylase and synthesizing 1, 5-pentanediamine by utilizing a whole-cell catalysis technology. Compared with a traditional chemical method and a natural enzyme method, the method disclosed by the invention has the advantages of simplified process, high catalytic efficiency, low production cost and the like, and is suitable for producing bio-based 1, 5-pentamethylene diamine and nylon 56 salt.

The invention discloses an anti-scale cross-linked polymer fracturing fluid and a preparation method thereof, and relates to the technical field of petroleum fracturing fluids. When the anti-scale cross-linked polymer fracturing fluid is prepared, allylamine hydrochloride and epoxy chloropropane react to prepare a double-bond chlorinated intermediate; reacting the double-bond chlorinated intermediate with lauramidopropyl dimethylamine to prepare a cationic monomer; copolymerizing a cationic monomer and acrylamide to prepare a cationic polymer; the preparation method comprises the following steps: reacting L-lysine with formaldehyde and phosphorous acid to prepare phosphoric acid modified lysine; reacting the phosphoric acid modified lysine with allyl glycidyl ether to prepare a phosphoric acid modified monomer; acrylamide and an anionic monomer are copolymerized to prepare an anionic polymer; the anionic polymer and the cationic polymer are dissolved in water to prepare the anti-scale cross-linked polymer fracturing fluid. The anti-scale cross-linked polymer fracturing fluid prepared by the invention has the advantages of scale prevention, good temperature resistance, good shear resistance and self-crosslinking.

The invention belongs to the field of skin care products, and particularly relates to an anti-wrinkle and anti-aging composition as well as a preparation method and application thereof, and the anti-wrinkle and anti-aging composition comprises neurotransmitter inhibition peptide, signal peptide, madecassoside, inositol and glycosylglycerol. The neurotransmitter inhibition type peptide is at least three of acetyl hexapeptide-8, arginine / lysine polypeptide, dipeptide diaminobutyrylbenzylamide diacetate and acetyl octapeptide-3, and the signal type peptide is at least two of palmitoyl pentapeptide-4, decapeptide-4 and acetyl tetrapeptide-9. Compared with the prior art, all the components of the anti-wrinkle and anti-aging composition act on different anti-aging pathways and can be matched with one another from multiple aspects of oxidation resistance, inflammation resistance, moisturizing, cell viability enhancement, wrinkle reduction and the like, a more comprehensive and better anti-aging effect is provided, skin aging is comprehensively resisted, the skin is in a more young state, and the anti-wrinkle and anti-aging composition has the advantages that the anti-wrinkle and anti-aging effects are achieved. And the anti-wrinkle and anti-aging composition is small in irritation and good in stability.

The invention belongs to the technical field of biological medicine, and discloses an engineering bionic exosome with an anti-aging effect and a preparation method and application thereof, and the preparation method comprises the following steps: (S1) preparing a bionic cell membrane modified targeting ligand: adding collagen, mitochondrial targeting polypeptide, a condensing agent and 4-dimethylaminopyridine into an organic solvent, and stirring to obtain the bionic cell membrane modified targeting ligand; activating under a protective atmosphere, and then adding lysine into the system to react, so as to obtain a bionic cell membrane modified targeting ligand; and (S2) embedding the bionic cell membrane modified targeting ligand into the engineered exosome bionic membrane, and entrapping an active substance to form the engineered bionic exosome. The exosome provided by the invention has better skin permeability, mitochondrial targeting effect and cell endocytosis effect, has better protection effect on mitochondria, and can realize efficient delivery of active substances.

The invention discloses a full D-type antibacterial peptide with high enzymolysis stability and broad-spectrum antibacterial activity and application thereof. The antibacterial peptide is obtained by sequentially and repeatedly arranging D-type tryptophan, D-type arginine and D-type lysine for four times and carrying out C-terminal amidation; the amino acid sequence of the gene is (D-Trp)-(D-Arg)-(D-Lys)-(D-Trp)-(D-Arg)-(D-Lys)-(D-Trp)-(D-Arg)-(D-Lys)-(D-Trp)-(D-Arg)-(D-Lys)-(D-Trp)-(D-Arg)-(D-Lys)-NH2, and is marked as DWRK-12. The antibacterial peptide shows broad-spectrum antibacterial activity and excellent stability, can effectively resist clinically separated multidrug resistant strains, and keeps high cell selectivity at the same time. Due to the characteristics, the antibacterial peptide has important application value in the aspect of developing novel antibacterial drugs, especially in the field of treatment of infection of multiple drug-resistant bacteria.

The invention discloses a macromolecular antibacterial agent, an antibacterial nylon material as well as a preparation method and application thereof, and relates to the technical field of antibacterial macromolecular materials. According to the invention, lysine is used as a raw material, the polymer antibacterial agent is prepared through reactions such as dehydration ring formation and re-ring opening polymerization, the polymer antibacterial agent has the characteristics of high safety, biodegradability and good biocompatibility, and has the same polyamide main chain structure as nylon, the polymer antibacterial agent and nylon have good compatibility, and the polymer antibacterial agent and nylon 6 are fused and blended to form a nylon 6 sample. Through amide exchange reaction and hydrogen bond interaction between the macromolecular antibacterial agent and nylon 6 molecular chains, the antibacterial nylon material with excellent mechanical property and lasting and stable antibacterial effect is prepared, and the requirements of people for safety and environmental friendliness are met. The prepared antibacterial nylon material can be applied to antibacterial products such as textiles, daily necessities and packaging materials. Meanwhile, the macromolecular antibacterial agent and the antibacterial nylon material are simple in preparation process, low in raw material cost and suitable for industrial production.

The invention discloses a cyclic nonapeptide with repairing and anti-oxidation effects and application of the cyclic nonapeptide, the amino acid sequence of the cyclic nonapeptide is cyclic (arginine-glycine-aspartic acid-serine-arginine-lysine-valine-lysine-serine), the prepared cyclic nonapeptide has the repairing and anti-oxidation effects, and the cyclic nonapeptide has the repairing and anti-oxidation effects. The composition can be applied to preparation of cosmetics with repairing and / or anti-oxidation effects.

The invention provides a plant lactobacillus TH13, and the preservation number of the plant lactobacillus TH13 is CGMCC (China General Microbiological Culture Collection Center) NO.32112. The plant lactobacillus TH13 provided by the invention can be used for fermenting folium cortex eucommiae and enzymatically hydrolyzed bone meal, and the fermentation product of the plant lactobacillus TH13 has high content of chlorogenic acid, proline, glycine and lysine. The fermentation product can significantly improve the content of alkaline phosphatase (ALP) and osteocalcin (OCN) in mouse serum and reduce the content of tartrate-resistant acid phosphatase (TRACP). Therefore, the fermentation product can significantly improve the bone mineral density of the femur, increase the number of bone trabecula and significantly reduce the separation degree of the bone trabecula, thereby promoting bone formation of a mouse with senile osteoporosis, inhibiting bone resorption and improving senile bone loss and bone microstructure deterioration. The preparation method of the probiotic preparation containing the plant lactobacillus and the probiotic fermentation product is simple, and large-scale production can be realized.

The invention relates to a multi-effect bionic liposome transdermal repair carrier and a preparation method and application thereof.The multi-effect bionic liposome transdermal repair carrier comprises active ingredients and a nano-carrier, and the active ingredients comprise sialic acid, saccharomycetes / rice fermentation product filtrate, arginine / lysine polypeptide and vitamin E in the mass ratio of (1-10): (2-8): (0.1-1): (0.5-4); the nano-carrier is prepared from the following raw materials: phospholipid, an emulsifier, polyhydric alcohol and water. Compared with the prior art, the anti-aging, whitening and moisturizing composition has the advantages of enhancing skin moisturizing and anti-oxidation effects, promoting collagen synthesis and inhibiting tyrosinase to achieve remarkable anti-aging, whitening and moisturizing effects and the like.

The invention provides a recombinant humanized elastin with high biological activity as well as a preparation method and application thereof, and belongs to the technical field of genetic engineering and biological materials. 100% of the amino acid sequence of the elastin is derived from human elastin and is prepared by expression of genetically engineered bacteria; the protein has a typical beta-spiral hydrophobic structural domain and a lysine-rich hydrophilic structural domain, has a good bionic structure and functional characteristics, can significantly promote proliferation, adhesion and migration of human skin fibroblasts, also has excellent antioxidant, anti-wrinkle and anti-aging activities, and can be used for preparing a biomimetic protein. The hydrogel can be widely applied to the fields of skin repair dressings, injection implants, artificial skin, biomedical materials, functional skin care products and the like; in addition, the elastin is good in solubility, high in stability, mature in expression system and suitable for large-scale production.

The invention relates to a composition for improving mildness and stability of a sunscreen product and application of the composition. The composition comprises a sphingomonas fermentation product extract, bis (lauramide glutamine) lysine sodium and a wild soybean seed extract. The invention creatively discovers that the three components of the sphingomonas fermentation product extract, the bis (lauramide glutamine) lysine sodium and the wild soybean seed extract are compounded for use, have a synergistic effect and can play a role under a low addition amount, so that the stability of the sunscreen product is improved, the irritation is reduced, the use experience is improved, and the sunscreen effect is improved. And moreover, the cost is effectively and reasonably reduced, and great market potential and economic value prospects are achieved.

The invention provides milk exosome composite hydrogel as well as a preparation method and application thereof, and belongs to the technical field of medical materials. The milk exosome composite hydrogel provided by the invention is prepared from milk exosome, hyaluronic acid, epsilon-polylysine, 3-aminophenylboronic acid and tannic acid. The exosome is extracted from milk of a non-stem cell source; the molecular weight of the hyaluronic acid is 200 to 400 KDa. The invention provides a hydrogel carrier capable of loading a large amount of milk exosomes, and the hydrogel carrier can continuously release a large amount of milk exosomes and can give full play to the anti-oxidation and inflammation inhibition effects of the milk exosomes. In the aspect of wound healing, the milk exosome and the hydrogel carrier have a synergistic effect, so that the healing effect can be remarkably improved, and the healing period is shortened.

The invention relates to the technical field of antibacterial high polymer materials, in particular to an antibacterial nylon material as well as a preparation method and application thereof. The method comprises the following steps: carrying out anion ring-opening copolymerization on a seven-membered ring lysine monomer obtained by ring formation of lysine and a lactam monomer to obtain copolyamide, dissolving the copolyamide, and carrying out complete quaternization reaction by using halogenated hydrocarbon to obtain the antibacterial nylon material. The preparation method provided by the invention effectively avoids the problems of insufficient antibacterial property, obvious mechanical property reduction, poor thermal stability and the like of an antibacterial nylon material prepared by hydrochloric acid protonation in the prior art. Meanwhile, the seven-membered cyclic lysine monomer can be copolymerized without alkylation, the synthesis process is greatly simplified, the production efficiency is high, and the production cost is low. The prepared antibacterial nylon material has the characteristics of lasting and efficient antibacterial performance, high safety, environment friendliness, excellent mechanical property and thermal stability and the like, and can be widely applied to the fields of textiles, daily necessities, packaging materials, panels and the like.

The invention discloses lysinibacillus sp. For degrading alternaria alternata toxins and application of the lysinibacillus sp., and belongs to the technical field of microorganisms, the lysinibacillus sp. Is preserved in China Center for Type Microbiological Culture Collection, the preservation address is Wuhan University, Hubei Province, and the preservation number is CCTCC No.M20241816. The invention further discloses a preparation method of the lysinibacillus sp. According to the invention, the Lysinibacillus macroides capable of effectively reducing and degrading alternaria alternata toxin is obtained for the first time, and the quality of agricultural products (including aquatic products) is favorably improved.

The invention discloses a milk-flavor jelly-shaped intelligent response type suckling pig creep compound feed and a preparation method, relates to the technical field of animal feeds, and aims to solve the problems that a traditional feed is poor in palatability, nutrition release and physiological needs are mismatched, thermosensitive components are damaged by a high-temperature process and the like. And accurate release of nutrients is realized. The feed comprises an energy raw material, a protein raw material, intelligent response components (pH-sensitive sodium alginate microsphere loaded sodium butyrate / glutamine, temperature-sensitive xanthan gum-locust bean gum compound gel coated antibacterial peptide, and enzyme-sensitive lysine-lysine peptide bond cross-linked layer embedded glucose compound enzyme), a flavor system (vanillin microcapsules) and a konjac gum jelly matrix. A pH-temperature-enzyme triple response mechanism is adopted to adapt to the gastric acid gradient, body temperature fluctuation and pancreatin activity of suckling pigs; milk flavor slow release and nutrition release are in space-time synergy, and the ingestion frequency is increased by 40%; the konjac glucomannan matrix reduces dust, and the gel strength is greater than or equal to 750g / cm.

The present invention provides a phycocyanin-collagen composite hydrogel and its preparation method and application. The present invention utilizes transglutaminase to catalyze the combination of phycocyanin and collagen to form a new, more stable collagen; transglutaminase acts between protein molecules, utilizes lysine and glutamic acid in phycocyanin and collagen to transfer acyl groups, and cross-links to form new chemical bonds, thereby enhancing the binding strength of phycocyanin and collagen; the hydrogel prepared by the present invention can be used to prepare medical materials and combined with skin injury sites to solve the problem that traditional dressings are easy to adhere to wounds and easily penetrated by tissue fluid and become infected. In addition to ensuring basic air permeability, it reduces the adhesion of the dressing, increases moisture retention and antioxidant properties, and avoids secondary damage when replacing a new dressing. The hydrogel prepared by the present invention has a certain antioxidant capacity and can be used to prepare products with antioxidant effects.

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.

A boron carrying agent, a preparation method therefor, and a pharmaceutical formulation. The boron carrying agent contains compound 1, N-4-carboxyphenylboronic acid amide-threonine-phenylalanine-phenylalanine-tyrosine-glycine-glycine-serine-arginine-glycine-lysine-arginine-aspartic acid-aspartic acid-phenylalanine-lysine-threonine-glutamic acid-glutamic acid-tyrosine-cysteine, having a molecular formula of C114H158BN30O35S1 and a molecular weight of 2552.4, and further contains compound 2, N-4-carboxyphenylboronic acid amide-arginine-lysine-lysine-lysine-arginine-arginine-glutamine-arginine-arginine-arginine, and / or compound 3, N-4-carboxyphenylboronic acid amide-methionine-alanine-serine-methionine-threonine-glycine-glycine-glutamine-glutamine-methionine-glycine. Compounds 1-3 can serve as a targeted medicament for boron neutron capture therapy used for treating a cerebral glioma and a head and neck tumor.

The invention provides a composition with an instant and long-acting anti-aging effect and application thereof. The composition comprises a component A, a component B and a component C, the mass ratio of the raw materials is (1-10): (1-4): (0.05-0.2); the component A is prepared from the following components in parts by weight: 0.01 to 0.5 part of acetyl octapeptide-3, 0.01 to 0.5 part of dipeptide diaminobutyryl benzyl amide diacetate, 0.001 to 0.2 part of arginine / lysine polypeptide, 0.3 to 1 part of caprylyl glycol and 96 to 100 parts of water; the component B is prepared from the following components in parts by weight: 0.001 to 0.2 part of soluble collagen, 5 to 30 parts of glycerol, 0.01 to 0.5 part of sodium dihydrogen phosphate, 0.001 to 0.2 part of disodium hydrogen phosphate and 65 to 100 parts of water; and the component C is tripeptide-29. According to the invention, the quadruple wrinkle fading polypeptide is adopted to block wrinkles in a multi-target full-link manner, so that the product has a very good effect of fading various wrinkles in real time.

The invention discloses an ultrashort-sequence antibacterial peptide rich in lysine and tryptophan, an antibacterial peptide hydrogel and application of the ultrashort-sequence antibacterial peptide and the antibacterial peptide hydrogel. The preparation method comprises the following steps: combining lysine and tryptophan to obtain polypeptide containing five or six amino acids; then amidation is carried out on the C terminal of the polypeptide, fatty acid chain modification is carried out on the N terminal and side chain amino groups, the ultra-short sequence antibacterial peptide rich in lysine and tryptophan is obtained, and the antibacterial peptide has broad-spectrum antibacterial activity for resisting gram-positive and gram-negative bacteria. An antibacterial peptide micelle self-assembly experiment shows that C12-2KW can be self-assembled into stable hydrogel in a 7.17 mu M PBS (Phosphate Buffer Solution), the hydrogel internally has a compact net-shaped structure, can completely cover the peritoneal injury surface and physically isolate the peritoneal injury surface from surrounding tissues, and has a good effect on treating wound infection caused by MRSA (Methicillin-Resistant Staphylococcus Aureus); meanwhile, the compound has the effect of resisting intestinal wall and abdominal wall adhesion after an operation, is low in toxicity, has a very good application prospect in the aspect of preparing clinical antibacterial drugs, and is expected to become a candidate drug of a novel antibiotic.

The present invention discloses a pectin methylesterase mutant ΔDdPemA, its encoding gene, preparation method, and application. The pectin methylesterase mutant ΔDdPemA is obtained by mutating the amino acid at position 200 in the center of the substrate binding pocket of the wild-type pectin methylesterase DdPemA from a high-molecular-weight, branched valine to a low-molecular-weight alanine, and by mutating the amino acid at position 339 at the substrate inlet and outlet of the substrate binding pocket from a high-molecular-weight, branched valine to a basic lysine. The amino acid sequence and nucleotide sequence of the wild-type pectin methylesterase DdPemA are SEQ ID NO. 1 and SEQ ID NO. 2, respectively. The mutant enzyme provided by the present invention has significantly improved enzyme activity under weakly acidic conditions, solving the problem of insufficient catalytic activity of the wild-type pectin methylesterase under weakly acidic conditions and creating favorable conditions for the application of the enzyme in the fields of food, textiles, and feed processing.

The invention belongs to the technical field of bioengineering, and relates to a transaminase mutant, a recombinant genetically engineered bacterium and application of the transaminase mutant in catalytic synthesis of (R)-1-Boc-3-aminopiperidine.The transaminase mutant is obtained by conducting single-point or combined mutation on the 131 site and / or the 197 site of an amino acid sequence shown in SEQ ID NO.2; the mutation sites comprise that the 131 phenylalanine is mutated into aspartic acid, threonine or tyrosine, and / or the 197 lysine is mutated into arginine or leucine. Experimental results show that compared with wild type transaminase, the catalytic activity, the thermal stability and the organic solvent tolerance of the obtained mutants, especially single-point mutants MyTA1-F131Y and MyTA1-K197R and a combined mutant MyTA1-F131Y-K197R, are all remarkably improved, and compared with the wild type transaminase, the catalytic activity, the thermal stability and the organic solvent tolerance of the obtained mutants are all remarkably improved. The mutant MyTA1-F131Y-K197R can be used for efficiently catalyzing asymmetric amination of N-Boc-3-piperidone to synthesize (R)-1-Boc-3-aminopiperidine, the conversion rate of the (R)-1-Boc-3-aminopiperidine after the (R)-1-Boc-3-aminopiperidine reacts for 24 hours under the condition that the substrate concentration is 100 g / L can reach 90% or above, and the mutant MyTA1-F131Y-K197R has a good industrial application prospect.

The invention belongs to the field of fertilizers, and particularly relates to a foliar fertilizer with high amino acid synthesis efficiency and a preparation method thereof.The preparation method comprises the steps that spermidine is taken to be subjected to formic acid esterification modification, and formic acid esterification spermidine is obtained; the preparation method comprises the following steps: hydrolyzing 2, 4-epibrassinolide to obtain carboxylated brassinolide; under the action of Tween, carboxylated brassinolide and formic acid esterified spermidine are combined to form a fertilizer base full of emulsified liquid drops; and adding other nutrients to obtain the foliar fertilizer. The leaf fertilizer for increasing the amino acid content of rice can increase the content of amino acids, especially lysine, in grains on the premise of increasing the yield of rice, and nitrogen absorption and utilization of the rice grains are improved.