37 results about "Amino-acid racemase" patented technology

The invention discloses fructose amino acid oxidase which has an amino acid sequence shown as SEQID.No.1 (sequence identifier number 1) or has above 80% homology with the amino acid sequence. One or more amino acid residues in corresponding positions of amino acid selected from (a) to (f) are substituted. The obtained fructose amino acid oxidase has higher thermostability: (a) 59-site glutamic acid, (b) 98-site glutamic acid, (c) 225-site glycine, (d) 277-site lysine, (e) 283-site glutamic acid and (f) 355-site aspartic acid. The invention further discloses a preparation method of the oxidase and a kit comprising the oxidase and used for determining glycatedalbumin. The kit has higher thermostability and can accurately determine the glycatedalbumin.

The invention relates to a method for preparing a chiral compound based on splitting by adopting a biological enzyme preparation, in particular to a method for preparing an L-tertiary leucine compound by a two enzyme system. The method prepares the chiral L-tertiary leucine compound of the formula III by using the reaction of an N-acylating tertiary leucine compound of the formula II in water or a buffer solvent at 15 to 60 DEG C in the presence of the two enzyme system. The biological enzyme is a mixed enzyme of an acylating amino acid racemase (alanine racemase) and a hydrolase; and the preparation reaction equation is as follows, wherein X is any group of OH, NH2, NR1R2 and OR3 (wherein R1, R2, R3 are a C1-C5 straight chain, a branch chain and a one, two or three-halogen substituted alkane respectively). The invention can be implemented at room temperature and ensures simple operation and no pollution, while remarkably lowering the production cost.

The invention provides a Delta 5 fatty acid desaturase from ocean microalgae, and coding gene and an application thereof. The inventive Delta 5 fatty acid desaturase has amino acid sequence shown in SEQ ID NO.2 or amino acid subjected to substitution, deletion or addition of one or more amino acid residues of the amino acid sequence and having the same functions. The inventive Delta 5 fatty acid desaturase can effectively catalyze the conversion of ETA(20:4 Delta 8,11,14,17) to EPA(20:5 Delta 5,8,11,14,17), and has the advantages of high specificity of substrate and high enzyme activity.

The invention discloses alpha-conus polypeptides and use thereof. The invention provides seven polypeptides: a polypeptide I of which the amino acid sequence is represented by a sequence 7 in a sequence table and in which the last amino acid residue is amidated; a polypeptide II of which the amino acid sequence is represented by a sequence 8 in the sequence table and in which the last amino acid residue is amidated; a polypeptide III of which the amino acid sequence is represented by a sequence 9 in the sequence table and in which the last amino acid residue is amidated; a polypeptide IV of which the amino acid sequence is represented by a sequence 10 in the sequence table and in which the last amino acid residue is amidated; a polypeptide V of which the amino acid sequence is representedby a sequence 11 in the sequence table and in which the last amino acid residue is amidated; a polypeptide vI of which the amino acid sequence is represented by a sequence 12in the sequence table andin which the last amino acid residue is amidated; and a polypeptide VII of which the amino acid sequence is represented by a sequence 13 in the sequence table and in which the last amino acid residueis amidated. The result of activity tests, the seven polypeptides of the general formula (I) have pain relieving effect, alpha-conus polypeptides T-1, T-2, T-3 and T-4 have obvious pain-relieving activity, and the alpha-conus polypeptides T-5, T-6 and T-7 also have obvious pain-relieving effect, and the alpha-conus polypeptides have application values in pain-reliving aspect.

The invention relates to a synthesis method of D-threonine (I). The method comprises the following steps: preparing D-allothreonine (V) from L-threonine (VI) serving as a raw material through racemization of amino acid racemase, action of L-threonine deaminase and purification sequentially; performing esterification on D-allothreonine (V) serving as a starting material to obtain an intermediate (IV); protecting amino by using benzoyl to obtain a compound of a formula (III); performing intramolecular cyclization on the compound of the formula (III) in the presence of sulfoxide chloride and turning over the spatial configuration of hydroxyl to obtain an oxazoline intermediate (II); performing ring opening on the intermediate (II) under the action of acid and removing a protecting group to obtain D-threonine (I). The synthesis method of D-threonine (I) is smart in design, the starting materials are cheap and readily available, the process flow is simple and practical, and a new method is provided for producing D-threonine on a large scale.

The invention relates to a preparation method of D-amino acid. The method comprises the steps of 1, the constructing of recombinant bacteria: an N-acetyl-D-aminoacylase gene is cloned, and the gene isconnected to a pET series carrier or a pKK 223-3 carrier and transformed to BL21 (DE3) host bacteria to construct D acylase recombinant bacteria (NLase); an N-acetyl-amino acid racemase gene is cloned, the gene is connected to the pET series carrier of the pKK223-3 carrier, transformed to the BL21(DE3) host bacteria to construct N-acetylamino acid racemase recombinant bacteria (NAAR); 2, recombinant bacteria fermentation; 3, immobilized enzyme preparation; 4, immobilized enzyme transforming combining with membrane separation; 5, product crystallization. By means of the method, the cost of theenzyme is reduced, the inhibition on the racemase of byproduct acetic acid is reduced, meanwhile, the transformation solution has little impurity, the separation and purification are simple, the yield is high, the product quality is good, the e.e. value of the obtained D-amino acid reaches 99.9% or above, the content is 99% or above, and the mole yield reaches 85% or above.

The present invention provides a novel peptide having bone formation-promoting effect and chondrocyte growth-promoting effect, in particular, a peptide having osteoblast growth-promoting activity, having 100 amino acid residues or less comprising an amino acid sequence selected from

(a) Val-Asn-Pro-Glu-Ser-Glu-Glu-Glu-Asp-Glu-Ser-Ser-Pro-Tyr-Glu (SEQ ID NO: 1),

(b) an amino acid sequence derived from the amino acid sequence (a) by conservative substitution or deletion of 1 to 3 amino acids, and

(c) an amino acid sequence consisting of at least four contiguous amino acids of the amino acid sequence (a) or (b), or

a derivative thereof or a salt thereof.

The invention belongs to the field of biotechnology, and relates to a method for preparing D-amino acid and alpha keto acid. The method includes the first step of recombinant construction: conductingwhole gene synthesis to obtain an L-amino acid deaminase gene LAAD and connecting an expression vector to be transformed into an expression strain to construct a recombinant PMLAAD; conducting whole gene synthesis to obtain an amino acid racemase gene AAR and connecting the expression vector to be transformed into the expression strain to construct a recombinant AAR; the second step of fermentation; the third step of enzyme catalysis; the fourth step of isolation and purification. The alpha-keto acid calcium and the D-amino acid are produced by enzyme catalysis, and both products have economicvalue and high product quality, so that the production cost is greatly reduced.

The invention discloses engineering bacteria for producing D-tryptophan and a construction method and a purpose of producing D-tryptophan. The construction method comprises the following steps: transferring an acylated amino acid racemase mutant gene and a N-acetyl-D-amino acid acyl hydrolase mutant gene in escherichia coli, and constructing the engineering bacteria for producing D-tryptophan. Theconstruction method optimizes the N-acetyl-D-amino acid acyl hydrolase mutant gene and the acylated amino acid racemase mutant gene, the acyl hydrolysis activity of the N-acetyl-D-tryptophan by the N-acetyl-D-amino acid acyl hydrolase and the racemization activity of the N-acetyl-L tryptophan by the acylated amino acid racemase are increased, and the output and the product quality of the D-tryptophan are increased. Two types of enzymes can be expressed by the same engineering bacterial strain, the fermentation cost is saved, and the production technology is simplified.

The invention discloses a method for producing DL-tyrosine by an enzyme, and a broad-spectrum amino acid racemase and use thereof. The method for producing DL-tyrosine by the enzyme comprises the following steps: S1, constructing a recombinant expression vector pET32a-PH0138 and transforming the recombinant expression vector into escherichia coli BL21(DE3)/pG-KJE8 to obtain a recombinant engineering bacteria BBAR; S2, fermenting the recombinant engineering bacteria BBAR expressing a BAR enzyme to obtain wet bacteria body; S3, suspending the wet bacteria body and crushing the bacteria with a crushing solution containing crude enzyme liquid of a broad-spectrum amino acid racemase; and S4, adding L-tyrosine and PLP into the crude enzyme liquid obtained in step S3, conducting stirring and converting until specific rotation is 0 degree and terminating the reaction to obtain a DL-tyrosine aqueous solution. The method has advantages of low raw material price, high conversion rate, simple post-treatment and high product quality, and is suitable for industrial mass production.

The invention discloses a method for synthesizing dipeptide with glutamic acid as the first amino acid residue. The method comprises the following steps: protecting the amino group of glutamic acid-5 methyl ester serving as an initial raw material by using carbobenzoxy; reacting with dicyclohexyl carbodiimide and N-hydroxy succinimide to prepare a high-purity midbody; further reacting with another group of amino acid under the alkali condition to obtain protected dipeptide; finally hydrogenating to obtain high-purity dipeptide which takes glutamic acid as the first amino acid residue. The method is environment-friendly, simple to operate, nearly free of waste discharge and beneficial to industrial production.

An isoamylase having improved heat resistance and an industrial method for producing maltose from starch.

The isoamylase is an isoamylase consisting of the amino acid sequence represented by SEQ ID NO: 1 or an isoamylase resulting from deletion, substitution, or insertion of one to several amino acid residues in the amino acid sequence represented by SEQ ID NO: 1, wherein at least valine at amino acid number 515 and methionine at amino acid number 570 are mutated to other amino acids.

The invention discloses a method for preparing gamma-carbonyl carboxylic acid, amino acid, amino acid ester and amide compounds. The method comprises the following steps: uniformly mixing a methylene-containing compound, an oxidizing agent and water to perform selective methylene carbon-hydrogen bond oxidation, so as to obtain at least one of gamma-carbonyl carboxylic acid, gamma-carbonyl amino acid and gamma-carbonyl amide compounds after the reaction is finished. The method is a methylene selective oxidation reaction which does not need a catalyst for catalysis and employs a persulfate as an oxidizing agent, and the reaction is successfully applied to oxidation of methylene carbon-hydrogen bonds of carboxylic acids, amino acids and amide compounds, excellent selectivity is obtained, and the method has important application value.