454 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 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.

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 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 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 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 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.

The invention provides an SNP (Single Nucleotide Polymorphism) marker for targeted identification of systemic lupus erythematosus of children and application of the SNP marker. A new SNP site (RS25671007) is identified in a child systemic lupus erythematosus patient through whole exon sequencing, the site is located at the 734th pair of basic groups of a PABPC3 gene, and mutation from C to T exists at the site, or mutation from threonine to isoleucine exists in coded amino acid. In addition, in-vitro cell model experiments prove that the SNP causes significant up-regulation of the antibody type transformation function, and the SNP can be used as a reference marker for risk stratification or medication guidance of early targeted diagnosis, detection, gene evaluation and the like of systemic lupus erythematosus of children.

The present invention relates to the fields of agriculture, plant biotechnology, and molecular biology. Specifically, the present invention relates to a wheat EPSPS mutant protein and use thereof in improving the tolerance of wheat to glyphosate. The mutant protein comprises an amino acid sequence having the following mutations compared to the EPSPS amino acid sequence of any genome of wild-type wheat: in the amino acid sequence set forth in SEQ ID NO: 2, the amino acid at position 168 is mutated from threonine to isoleucine, the amino acid at position 169 is mutated from alanine to valine, and the amino acid at position 172 is mutated from proline to serine. The mutant protein enables the production of stable glyphosate-resistant wheat, showing important significance for wheat breeding.

The invention relates to aspartate kinase for relieving feedback inhibition of L-threonine and application of aspartate kinase, and belongs to the field of enzyme engineering and metabolic engineering. The mutant is obtained by carrying out E253K and / or K507E mutation on the basis of wild type aspartate kinase as shown in SEQ ID NO.1, the enzyme activity of the mutant is not obviously changed under the condition that the concentration of L-threonine is 0-12 mmol / L, and the feedback inhibition effect of L-threonine on the mutant is relieved. The method can be widely applied to synthesis of essential amino acids including L-threonine, L-tryptophan, L-isoleucine, L-lysine, L-leucine, L-valine, L-methionine, L-phenylalanine and the like.

The invention belongs to the technical field of biology, and discloses a transaminase GabT1 mutant S106I, a construction method thereof and application of the transaminase GabT1 mutant S106I in biosynthesis of 1-deoxynojirimycin. According to the invention, the 106th serine near the molecular catalytic domain of the transaminase GabT1 derived from bacillus amyloliquefaciens is mutated into isoleucine in a site-directed mutagenesis manner, so that the catalytic efficiency of the transaminase GabT1 is remarkably improved, the problem that the catalytic efficiency of the transaminase GabT1 on fructose-6-phosphoric acid is not high at present is solved, and the application of the transaminase GabT1 to the fructose-6-phosphoric acid is promoted. The yield of 1-deoxynojirimycin synthesized by the mutant GabTS106I is increased by 43.87% compared with that of a wild type. The 1-deoxynojirimycin fermentation production capability of the transaminase GabT1 mutant and the engineering strain obtained by the invention is greatly improved, and the transaminase GabT1 mutant and the engineering strain have a good industrial application prospect.

An Fc-binding polypeptide with improved alkaline stability comprising a mutant of the Fc-binding domain of Staphylococcus protein A (SpA), said mutant being defined by SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 22, SEQ ID NO 51 or EQ ID NO 52, wherein at least the asparagine or serine residue at a position corresponding to position 11 in SEQ ID NO: 4-7 has been mutated to an amino acid selected from the group consisting of glutamic acid, lysine, tyrosine, threonine, phenylalanine, leucine, isoleucine, tryptophan, methionine, valine, alanine, histidine and arginine.

The present invention addresses the problem of providing a composition for lyophilizing extracellular vesicles or artificial cell vesicles, which makes it possible to prevent the extracellular vesicles or the artificial cell vesicles from being deteriorated in shape preserving properties or functions thereof or from being reduced in particle diameters when the extracellular vesicles or the artificial cell vesicles are recovered by hydration after lyophilization. The composition for lyophilizing extracellular vesicles or artificial cell vesicles is prepared, the composition being characterized by being intended to be added to extracellular vesicles or artificial cell vesicles upon use and also being characterized by containing the following hydrophobic substances: (a) phenylalanine or a methyl ester thereof; (b) a dipeptide which is composed of one or two kinds of hydrophobic amino acids selected from the group consisting of phenylalanine, leucine, glycine, valine, isoleucine, tryptophan, and alanine and contains at least one phenylalanine molecule as a constituent amino acid; and the like.

The present invention relates to the field of biotechnology, and more particularly to enzyme mutants and their applications in the preparation of isoleucyl arginine. The present invention has discovered an amino acid ligase (Uniprot: A0A2W4HG92) capable of connecting L-isoleucine and L-arginine to synthesize isoleucyl arginine. Based on the enzyme, modification was carried out, and by mutating the amino acid residues in its catalytic activity pocket and other related positions, an enzyme mutant with high catalytic activity was finally obtained, which greatly increased the yield of isoleucyl arginine. This method is significantly superior to chemical synthesis preparation processes, not only increasing the yield of the product, but also showing outstanding advantages in production cost, energy consumption, product quality and green index, and is suitable for large-scale production.

The application relates to the technical field of beef cattle breeding, and particularly discloses a compound preparation for promoting the feed intake, daily weight gain and improving the meat quality of beef cattle and application thereof, which is prepared from the following components in percentage by volume: 40% of micro-ecological preparation, 30% of hawthorn, 10% of medicated leaven, 10% of malt, 5% of areca nut and 5% of dried tangerine or orange peel; the compound preparation is prepared from microorganisms and multiple natural Chinese herbal medicines in a specific and scientific matching ratio; experiments prove that the compound preparation can increase the feed intake of beef cattle by 11.33%, increase the daily weight gain by 16.16%, and significantly shorten the breeding cycle; meanwhile, the contents of aspartic acid, threonine, glutamic acid, alanine, valine, isoleucine, leucine, tyrosine, phenylalanine, lysine, arginine and proline in the muscle are significantly increased, the nutritional quality and flavor taste of beef are effectively improved, the preparation is natural, residue-free and side-effect-free, the preparation method is simple, the cost is low, and the preparation has extremely high practical value and popularization prospect.

This invention provides a ketolic acid reductase mutant and its application in constructing genetically engineered bacteria that produce high levels of D-pantothenic acid. To address the technical problem of low D-pantothenic acid yield in existing microbial fermentation, this invention utilizes semi-rational enzyme design to obtain a substrate-specific ketolic acid reductase mutant, which is then applied to construct genetically engineered bacteria that produce high levels of D-pantothenic acid. Furthermore, this invention employs CRISPR-Cas9 gene editing technology to construct genetically engineered bacteria that produce high levels of D-pantothenic acid using the aforementioned ketolic acid reductase mutant, increasing D-pantothenic acid production by approximately 12.04%. Compared to the starting strain, the accumulation of valine in the fermentation broth remained almost unchanged compared to the control, but the accumulation of the branched-chain amino acid isoleucine was lower, achieving substrate-specific modification of the ketolic acid reductase.

The present application relates to a microorganism capable of producing L-isoleucine, into which a gene encoding an exogenous glutamate dehydrogenase has been introduced, a method for producing L-isoleucine using the microorganism, and a composition for producing L-isoleucine containing the microorganism.

The invention discloses a method for detecting an instant branched chain amino acid free monomer. The method comprises the following steps: preparing water, acetonitrile, methanol, a hydrochloric acid solution, an acetic acid solution, a sodium hydroxide solution, an OPA solution, a borate buffer solution, an acetate buffer solution I, an acetate buffer solution II, a leucine reference substance, an isoleucine reference substance and a valine reference substance; the device comprises a high performance liquid chromatograph, a liquid chromatography processor, a chromatographic column, an analytical balance and a centrifugal tube, the detection method comprises the following steps in sequence: preparing a contrast solution, preparing a sample solution, determining the sample solution and the contrast solution, and calculating a result. And an efficient quantitative detection scheme of the instant branched chain amino acid free monomer is provided.