560 results about "Isoleucine" patented technology

The invention provides a keto-alcohol acid reductoisomerase mutant and application of the keto-alcohol acid reductoisomerase mutant in construction of genetically engineered bacteria for high yield of D-pantothenic acid. In order to solve the technical problem that in the prior art, the yield of D-pantothenic acid synthesized through microbial fermentation is not high, semi-rational design of enzyme is adopted, and a keto-alcohol acid reductoisomerase mutant with substrate specificity is obtained and applied to construction of genetically engineered bacteria for high yield of D-pantothenic acid. According to the invention, a genetically engineered bacterium with high yield of D-pantothenic acid is constructed by utilizing the keto-alcohol acid reductoisomerase mutant through a CRISPR-Cas9 gene editing technology, so that the yield of D-pantothenic acid is increased by about 12.04%, and compared with an original strain, the valine accumulation amount in obtained fermentation liquor is almost unchanged compared with that of a control, and the yield of D-pantothenic acid is greatly improved. However, the accumulation of branched chain amino acid isoleucine is less, so that the modification of the substrate specificity of the keto-alcohol acid reductoisomerase is achieved.

The invention relates to the technical field of gene engineering and enzyme engineering, in particular to an esterase mutant for degrading ethyl carbamate and application of the esterase mutant, the esterase mutant has an amino acid sequence as shown in SEQ ID NO.1 which is subjected to site mutation, the site mutation is any one or more site combined mutation of V129S, V161L or I229M, and the amino acid sequence of the esterase mutant is shown in SEQ ID NO.1. The V129S site mutation is that valine at the 129 site is mutated into serine, the V161L site mutation is that valine at the 161 site is mutated into leucine, and the I229M site mutation is that isoleucine at the 229 site is mutated into methionine. Mutation is carried out through a site-directed mutagenesis method, so that the amino acid sequence of the esterase mutant V129S / I229M is changed, the autoplasmic structure and function of eggs are changed, the esterase mutant V129S / I229M with the ethyl carbamate hydrolysis rate increased to 6.55 times in an acid environment is finally obtained, and the esterase mutant V129S / I229M has high industrial application value.

The invention discloses application of a low-toxicity broad-spectrum antibacterial peptide taking WW as a symmetric center, WK is repeated twice and symmetrically distributed on two sides, WW is taken as the symmetric center to obtain an antibacterial peptide WKWKWWKWKW-NH2 (N2W2), and tryptophan at the C terminal and the N terminal of the N2W2 is replaced with leucine and / or isoleucine to obtain the antibacterial peptide. The antibacterial peptide can basically maintain the excellent antibacterial activity of the parent peptide, and the hemolytic activity of the antibacterial peptide is greatly reduced, so that the safety is improved. Wherein the antibacterial activity of IL-N2W2 is the highest, but the stability of IL-N2W2 needs to be improved, so that D-IL-N2W2 is obtained by carrying out D-type amino acid substitution on IL-N2W2. The D-IL-N2W2 keeps the high antibacterial activity and low toxicity of IL-N2W2, can still completely inhibit the growth of bacteria after being incubated with high-concentration trypsin or chymotrypsin, has great potential in the aspect of relieving the drug resistance of antibiotics, and has good application prospects in preparation of clinical antibacterial drugs.

The invention provides a fluorescent protein selection marker staygold-ynaMr gene and application thereof, and belongs to the technical field of biological engineering. The method comprises the following steps: replacing codons of L-isoleucine in nucleotide sequences of a fluorescent protein gene staygold and a gene ynaM by using a rare codon ATA to respectively obtain the fluorescent protein gene staygold after codon replacement and the gene ynaMr after codon replacement, and connecting the two segments of genes after codon replacement by using a flexible protein peptide, and the fluorescent protein selection marker staygold-ynaMr gene is obtained. Experiments prove that the gene can obviously improve the screening efficiency of L-isoleucine high-yield strains.

Composition for use in the prevention and / or treatment of a liver disease in a mammal, the composition comprising an active agent, said active agent containing the amino acids leucine, isoleucine, valine, threonine, lysine and the carboxylic acids citric acid, succinic acid, malic acid.

The invention discloses a high-activity TET dioxygenase mutant as well as a construction method and application thereof. The TET dioxygenase mutant is obtained from an amino acid sequence of wild type TET dioxygenase as shown in SEQ ID NO.1 according to any one of the following mutation modes: a, the 150th proline is mutated into alanine; and b, proline at the 150th site is mutated into alanine, and isoleucine at the 235th site is mutated into methionine. The TET dioxygenase mutant provided by the invention can be stabilized in an escherichia coli system, the purification effect is good, the preparation difficulty is reduced, and the activity is remarkably improved compared with that of a wild type. The methylation gene transformation effect is far better than that of a traditional bisulfite transformation method, and the method has a good application prospect.

The invention relates to the technical field of functional product preparation, and provides a rhizoma polygonati and saussurea involucrata bone marrow peptide tablet as well as a preparation method and application thereof. The rhizoma polygonati and saussurea involucrata bone marrow peptide tablet is prepared from the following components: collagen peptide powder, L-isoleucine, a compound nutrient supplement, rhizoma polygonati, sorbitol, yak bone marrow peptide powder, fructus phyllanthi, fructus alpiniae oxyphyllae, mulberry powder, a saussurea involucrata culture and magnesium stearate. All the components of the rhizoma polygonati and saussurea involucrata bone marrow peptide tablet disclosed by the invention have a synergistic effect, so that the effects of conditioning sub-health, maintaining joints and assisting in treating diseases can be achieved.

The invention provides a branched chain amino acid transaminase gene and application thereof, and belongs to the field of gene engineering. According to the invention, the branched chain amino acid transaminase gene HvBCAT5 is found for the first time, and the gene has obvious positive correlation with the accumulation of valine (Val), isoleucine (Ile) and leucine (Leu) of crops. The invention provides an important target gene HvBCAT5 for crop quality improvement, and has important value for increasing the content of branched chain amino acid of crops and improving dietary nutrition. The HvBCAT5 gene as well as a recombinant vector, a recombinant bacterium and a transgenic plant thereof have good application prospects in the fields of food and feed industry.

The invention discloses corynebacterium glutamicum for producing L-isoleucine and application of the corynebacterium glutamicum. The strain is obtained by performing ultraviolet mutagenesis and structural analogue resistance screening on corynebacterium glutamicum ATCC13869. According to the method, the L-isoleucine can be produced through direct fermentation of glucose, the yield of the L-isoleucine can reach 51.69 g / L, the conversion rate can reach 28.5%, the production efficiency is improved, meanwhile, the main raw material glucose used for fermentation is low in price and easy to obtain, the method conforms to the green food safety production concept, and industrial production of the L-isoleucine is facilitated.

The invention provides a keto-alcohol acid reductoisomerase mutant and application of the keto-alcohol acid reductoisomerase mutant in construction of genetically engineered bacteria for high yield of D-pantothenic acid. In order to solve the technical problem that in the prior art, the yield of D-pantothenic acid synthesized through microbial fermentation is not high, semi-rational design of enzyme is adopted, and a keto-alcohol acid reductoisomerase mutant with substrate specificity is obtained and applied to construction of genetically engineered bacteria for high yield of D-pantothenic acid. According to the invention, a genetically engineered bacterium with high yield of D-pantothenic acid is constructed by utilizing the keto-alcohol acid reductoisomerase mutant through a CRISPR-Cas9 gene editing technology, so that the yield of D-pantothenic acid is increased by about 12.04%, and compared with an original strain, the valine accumulation amount in obtained fermentation liquor is almost unchanged compared with that of a control, and the yield of D-pantothenic acid is greatly improved. However, the accumulation of branched chain amino acid isoleucine is less, so that the modification of the substrate specificity of the keto-alcohol acid reductoisomerase is achieved.

The invention discloses intestinal bacteria and serum metabolites which can be used as biomarkers of type 2 diabetes mellitus (prediabetes mellitus (PDM), new diagnosis diabetes mellitus (NDDM) and diabetes mellitus (P2DM) after medication) in different disease stages, and application of the intestinal bacteria and the serum metabolites. Aiming at type 2 diabetes mellitus, predictive markers including staphylococcus aureus, escherichia coli, klebsiella pneumoniae, branched chain amino acids (leucine, valine and isoleucine) and the like, especially staphylococcus aureus of which the genome contains acetolactate synthase (ALS), are efficiently screened out. The type 2 diabetes mellitus marker disclosed by the invention can be used for early warning the illness risk of type 2 diabetes mellitus and guiding the adjustment of an intestinal microbial environment; the method can be used for indicating the correlation between the intestinal microbial environment and the type 2 diabetes mellitus and is used for assisting diagnosis; and drug action target research, accurate medication, pathogenesis research and the like are realized.

The embodiment of the invention provides a fermentation method of L-leucine and L-isoleucine. According to the method, at least one L-leucine or L-isoleucine producing strain is used for fermentation culture; according to the method, relatively cheap molasses with rich carbon and nitrogen sources is selected as materials, corn steep liquor with more impurities is abandoned, and the molasses is converted into a nutrient substance containing more carbon and nitrogen sources capable of being utilized by strains through enzymolysis; in addition, in order to control the ratio of carbon and nitrogen sources in the fermentation liquor, a more accurate material supplementing process is selected, so that the fermentation requirements of strains can be guaranteed, and the situation that the liquid nitrogen source of the fermentation liquor is too high and too low can be effectively avoided, and the purposes of increasing the yield and the sugar acid conversion rate and reducing heteroacid byproducts are achieved.

The invention belongs to the technical field of genetic engineering and enzyme engineering, and particularly relates to a genetically engineered bacterium for stably and efficiently producing L-isoleucine as well as a construction method and application of the genetically engineered bacterium. The genetically engineered bacterium takes E. coliTHRD as a host and contains an RNA (Ribonucleic Acid) polymerase beta-subunit mutant coding gene rpoBM; compared with a parent RNA polymerase beta-subunit, the RNA polymerase beta-subunit mutant has the advantage that the amino acid residue at the 618th site of the amino acid sequence is sequentially replaced with leucine from the N terminal to the C terminal. The genetically engineered bacterium disclosed by the invention can tolerate L-isoleucine and accumulate less alpha-ketobutyric acid, and has a very good industrial application prospect.

The invention relates to the technical field of information, and discloses a method for predicting the optimal branched chain amino acid ratio of daily ration of lactating sows, which comprises the following steps of: 1, acquiring production data and feed formula data; 2, processing the production data and the feed formula data to obtain production sample data and formula sample data; 3, performing correlation calculation on the production sample data and the formula sample data to obtain most effective features and calculate feature vectors; 4, training a preset model according to the feature vector and the formula sample data; 5, verifying the preset model, and selecting an optimal prediction model according to an evaluation result; and 6, outputting an isoleucine content prediction value, a leucine content prediction value and a valine content prediction value by the optimal prediction model. The prediction method can accurately and reliably predict the branched chain amino acid proportion of daily ration with different protein levels. Meanwhile, the invention further provides a prediction device for the optimal branched chain amino acid proportion of the daily ration of the lactating sow.

The invention provides p-hydroxymandelic acid synthetase, a gene, a mutant of the p-hydroxymandelic acid synthetase and application of the p-hydroxymandelic acid synthetase in asymmetric synthesis of (S)-mandelic acid. The p-hydroxymandelic acid synthetase disclosed by the invention is derived from actinomycetes Actinokineospora auranticola, the amino acid sequence of the p-hydroxymandelic acid synthetase is as shown in SEQ ID NO.1, and a mutant of the p-hydroxymandelic acid synthetase is obtained by performing single-point mutation or multi-point combined mutation on glutamic acid at the 187th site, isoleucine at the 189th site and threonine at the 211th site of the amino acid sequence as shown in SEQ ID NO.1. The p-hydroxymandelic acid synthetase and the mutant thereof can convert phenylpyruvic acid into (S)-mandelic acid with high optical purity, have the advantages of mild reaction conditions, simplicity and convenience in operation, safety, environment friendliness and the like, and have a very good industrial application prospect.

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 provides a nicotinamide nucleotide transhydrogenase mutant and application thereof, valine at the 169th site of the nicotinamide nucleotide transhydrogenase mutant is designed to be mutated into isoleucine, the isoleucine is used for constructing a lysine production strain, and the new strain does not contain plasmids, does not have growth defects, does not need induction, and has the advantages of good genetic stability, high fermentation yield and the like. The lysine can be efficiently and stably produced from the beginning by taking glucose as a substrate.

The invention discloses a method for inhibiting production of vomitoxin from bacillus cereus, which is characterized in that isoleucine is added into a substance needing to inhibit production of vomitoxin from bacillus cereus, preferably 5-20mM of isoleucine is added. According to the present invention, the content of the toxin is detected through the liquid chromatography-mass spectrometry, and the cytotoxicity experiment verification results show that the isoleucine can significantly inhibit the synthesis of the vomitoxin of the bacillus cereus in the culture medium and the matrix, and can effectively reduce the toxic effect of the toxin on HeLa cells; the invention provides a safe and efficient biological control means which is suitable for various food systems such as starch food, dairy products, meat products and the like. Isoleucine can be used as a novel non-toxic and harmless food additive and is low in cost; the use method is simple, the output of vomitoxin can be reduced by directly adding a trace amount of isoleucine, and the food flavor is not affected.

The invention discloses a high-stability carbonyl reductase mutant and application of the high-stability carbonyl reductase mutant in chiral alcohol synthesis. An amino acid sequence as shown in SEQ ID NO.2 is mutated as follows: 20th leucine is replaced by any one of lysine, threonine, aspartic acid or isoleucine, and / or 55th leucine is replaced by any one of methionine, serine, lysine or isoleucine, and / or 55th leucine is replaced by any one of methionine, serine, lysine or isoleucine. Compared with a wild type enzyme, the stability of the obtained mutant is remarkably improved, particularly, single-point mutants Mut-L20I and Mut-L55I and a combined mutant Mut-L20I-L55I show excellent relative enzyme activity, thermal stability and substrate tolerance. The mutant has high catalytic activity and stability to various chiral alcohols, has the advantages of high catalytic efficiency, high thermal stability, strong substrate tolerance, easiness in fermentation production and the like, and is suitable for industrial application of enzymatic synthesis of chiral alcohols.

The present disclosure pertains to novel Glucagon like Peptide-1 (GLP-1) (7-37) analogs having an amino acid sequence with Leu or Ile at the C-terminal. The new analogs are potent GLP-1 agonists with reduced adverse effect and improved duration of action. The present disclosure further relates to acylated derivatives of the new analogs which have further improved potency and duration of action and are suitable for oral administration. The analogs of present disclosure may be useful in treatment of diabetes and obesity.

The present application relates to a pyridoxal kinase mutant, a recombinant expression vector and a microbial cell and their applications, and belongs to the technical field of biological catalysis. In order to solve the problem of low product concentration in existing enzyme catalysis, a pyridoxal kinase mutant is provided, the amino acid sequence is selected from the amino acid sequence shown in SEQ ID NO. 1, the lysine at position 229 is mutated to alanine, phenylalanine, methionine, arginine, threonine, histidine, serine, tyrosine, valine, leucine, isoleucine, proline, asparagine, aspartic acid or glutamic acid; the pyridoxal kinase mutant is used for catalyzing pyridoxal to synthesize pyridoxal phosphate, and a recombinant expression vector and a microbial cell can be further formed. The present application has good enzyme activity, high product conversion rate, high concentration of pyridoxal phosphate obtained, and the concentration of the product catalyzed by the wild-type pyridoxal kinase to phosphorylate pyridoxal is obviously improved.

The invention discloses a leucine dehydrogenase mutant and application thereof.The mutant is obtained by replacing any one or more amino acid residues in the 36th site, the 59th site and the 109th site on the basis of a wild leucine dehydrogenase amino acid sequence, compared with the wild leucine dehydrogenase amino acid sequence, the enzyme activity of the mutant is improved by 5 times or above, the LeuDH mutant is guided into host bacteria, and the activity of the LeuDH mutant is improved by 5 times or above. The obtained recombinant bacterium is used for fermentation production of L-isoleucine, the yield of L-isoleucine reaches 30 g / L or above, compared with a wild type, the yield is remarkably improved, and powerful support is provided for fermentation production of an L-isoleucine product.

The invention discloses an application of NCgl0762 protein and a mutant thereof in production of L-isoleucine, and belongs to the technical field of biology. The technical problem to be solved by the invention is how to improve the yield of L-isoleucine. The sequence of the protein disclosed by the invention is SEQ ID No. 4 or SEQ ID No. 2. The yield of the L-isoleucine can be increased by replacing the coding gene of the protein as shown in SEQ ID No.2 in starting organism cells with the coding gene of the protein as shown in SEQ ID No.4 or increasing the content or activity of the protein as shown in SEQ ID No.2 or SEQ ID No.4 in the starting organism cells.

The invention discloses a mycobacterium tuberculosis tyrosine phenol lyase mutant and application thereof, and belongs to the field of molecular biology and the technical field of biological catalysis. The mutant is obtained by mutating 384 isoleucine of tyrosine phenol lyase from mycobacterium tuberculosis into valine, and is marked as a mutant I384V. The I384V and wild type tyrosine phenol lyase have similar optimum temperature and optimum pH, but the I384V shows higher specific enzyme activity and catalytic efficiency than the wild type tyrosine phenol lyase. Compared with a wild type, the tyrosine phenol lyase mutant I384V has the advantages that the synthesis efficiency of the tyrosine phenol lyase mutant I384V on the synthesis of levodopa is improved by 38.4%, and the tyrosine phenol lyase mutant I384V has wide prospects in large-scale industrial application.

The invention discloses a rice ACCase mutant protein and a preparation method thereof. The amino acid sequence of the ACCase mutant gene encoding protein has the following mutations: the 2052nd site corresponding to the amino acid sequence of wild rice ACCase is mutated, isoleucine (I) is changed into asparagine (N), or isoleucine (I) is changed into glutamine (Q), or isoleucine (I) is changed into cysteine (C), or isoleucine (I) is changed into cysteine (C), or isoleucine (I) is changed into cysteine (C), or isoleucine (I) is changed into cysteine (C), or isoleucine (I) is changed into cysteine (C). And the plant can have extremely strong resistance (tolerance) to acetyl-coenzyme A carboxylase inhibitor herbicides. After the rice containing the rice ACCase mutant protein disclosed by the invention is applied with an acetyl-coenzyme A carboxylase inhibitor herbicide with 8 times of recommended use concentration, plants still grow normally, and the tolerance of the herbicide is greatly enhanced, so that the rice ACCase mutant protein can be widely applied to breeding of herbicide-resistant plants.

The invention discloses a preparation method of gardenia blue pigment. The preparation method comprises the following steps: (1) precipitating and removing impurities by copper sulfate: precipitating and removing impurities from column liquid after gardenia yellow is extracted by copper sulfate to obtain supernate; (2) oxidizing and decoloring by potassium permanganate and removing excessive copper ions: performing neutral oxidation on the supernate by potassium permanganate to obtain decolored supernate; (3) nanofiltration concentration and spray drying: carrying out alkaline nanofiltration concentration and spray drying on the decolorized supernatant to obtain a geniposide solid crude product; (4) extracting geniposide with propyl alcohol and recrystallizing: extracting the crude product with ethyl acetate and recrystallizing to obtain a fine geniposide product; (5) ethyl acetate two-phase acid hydrolysis: carrying out ethyl acetate two-phase acid hydrolysis and recrystallization on the refined product to obtain a genipin pure product; and (6) preparing a gardenia blue pigment pure product: reacting the genipin pure product with sodium isoleucine to obtain the gardenia blue pigment. The method is simple and easy to implement, convenient to operate, outstanding in product characteristics, easy in equipment type selection and matching, low in equipment investment, high in product additional value, good in economic benefit and capable of being mechanized.

The invention provides an extracellular matrix protein recombinant protein, a nucleic acid molecule, a recombinant vector, a genetically engineered bacterium, a preparation method and an application. The provided extracellular matrix protein recombinant protein comprises the following protein fragments: human fibronectin, humanized collagen and elastin-like protein. Wherein the amino acid sequence of the human fibronectin is as shown in SEQ ID NO. 1; the amino acid sequence of the humanized collagen is as shown in SEQ ID NO. 2; the elastin-like protein comprises a pentapeptide repetitive sequence, repetitive units of the pentapeptide repetitive sequence comprise-[valine-proline-glycine-Xaa-glycine] n-, Xaa is isoleucine or lysine, and the number n of the repetitive units is 15-30; in the extracellular matrix protein recombinant protein, any two adjacent ones of the human fibronectin, the humanized collagen and the elastin-like protein are independently connected through a peptide bond or a connecting peptide. The extracellular matrix recombinant fusion protein provided by the invention has good thermal stability and can promote cell adhesion.

The invention relates to a pyridoxal kinase mutant, a recombinant expression vector, a microbial cell and application thereof, and belongs to the technical field of biological catalysis. In order to solve the problem of low concentration of the existing enzyme catalysis product, the invention provides the pyridoxal kinase mutant. The amino acid sequence is selected from lysine at the 229 site of the amino acid sequence as shown in SEQ ID NO.1, and the lysine at the 229 site of the amino acid sequence as shown in SEQ ID NO.1 is mutated into alanine, phenylalanine, methionine, arginine, threonine, histidine, serine, tyrosine, valine, leucine, isoleucine, proline, asparagine, asparaginic acid or glutamic acid; the pyridoxal kinase mutant is used for catalyzing pyridoxal to synthesize pyridoxal phosphate, and recombinant expression vectors, microbial cells and the like can be further formed. The pyridoxal phosphate has good enzyme activity and high product conversion rate, the concentration of the obtained pyridoxal phosphate is high, and the concentration of a product obtained by catalyzing phosphorylation of pyridoxal through the pyridoxal phosphate kinase is obviously improved compared with that of a product obtained by catalyzing phosphorylation of pyridoxal through wild type pyridoxal kinase.

The invention relates to the technical field of biological catalysis, in particular to an immobilized formate dehydrogenase mutant and application of the immobilized formate dehydrogenase mutant in electroenzymatic catalysis of CO2. The formate dehydrogenase mutant comprises the following mutations on the basis of clostridium wild formate dehydrogenase: methionine at the 269th site is mutated into isoleucine, serine at the 285th site is mutated into alanine, and serine at the 637th site is mutated into alanine; the NCBI (National Center of Biotechnology Information) accession number of the wild formate dehydrogenase of the clostridium is WP082085143.1. The immobilized formate dehydrogenase mutant provided by the invention has better catalytic activity, temperature, pH stability and storage stability, and can be repeatedly utilized. The immobilized formate dehydrogenase mutant or an electrode material prepared from the immobilized formate dehydrogenase mutant can efficiently catalyze CO2 to be converted into formic acid or formate, which has important significance in the field of renewable energy utilization.

The invention provides a branched chain amino acid transaminase gene and application thereof, and belongs to the field of gene engineering. According to the invention, the branched chain amino acid transaminase gene HvBCAT1 is found for the first time, and the gene has obvious positive correlation with valine (Val) and isoleucine (Ile) accumulation of crops. The invention provides an important target gene HvBCAT1 for crop quality improvement, and has important value for increasing the content of branched chain amino acid of crops and improving dietary nutrition. The HvBCAT1 gene as well as a recombinant vector, recombinant bacteria and transgenic plants thereof have good application prospects in the fields of food and feed industry.