234 results about "L serine" patented technology

The invention relates to a method for preparing phosphatidylserine abundant in polyunsaturated fatty acid and belongs to the technical field of bioengineering. The method is characterized by comprising the following steps of: firstly, catalyzing ester exchange reaction between phosphatide and polyunsaturated fatty acid ester by utilizing one or a mixture of phosphatidase A and lipase to generate phosphatide abundant in polyunsaturated fatty acid; and then catalyzing phosphor-transfer esterification reaction between the phosphatide abundant in the polyunsaturated fatty acid and L-serine by utilizing phosphatidase D to generate the phosphatidylserine abundant in the polyunsaturated fatty acid. The method has the advantages of no discharge of waste water, good product quality, no solvent residue, safe process operation, few reaction byproducts, no waste generation, cost reduction, simple production process and easy realization of scale production because of utilizing two enzymes to perform sub-step catalysis and perform reaction in the same reactor, and completing the reaction process in a non-solvent system. Therefore, the invention provides a good and feasible method for preparing the phosphatidylserine abundant in the polyunsaturated fatty acid.

A microorganism is provided which has an ability to produce an L-amino acid such as L-lysine, L-tryptophan, L-phenylalanine, L-valine, L-leucine, L-isoleucine and L-serine, and has been modified to increase the activity of pyruvate synthase or pyruvate:NADP⁺ oxidoreductase. This microorganism is cultured in a medium containing ethanol or an aliphatic acid as the carbon source to produce and accumulate the L-amino acid in the medium or cells, and the L-amino acid is collected from the medium or the cells.

The invention relates to a method of preparing compounds, in particular to a method of preparing powder phosphatidylserine. The invention has to overcome the problems that the prior art inputs a lot of equipment and costs a lot, and the transformation ratio of the reaction is hard to be guaranteed. The invention has the technical proposal that a method of preparing powder phosphatidylserine takes natural lecithin as the reaction substrate; and after being separated by water, the reaction substrate can be added with an inorganic system prepared by L-serine, calcium salt and buffer solution to produce rough product under the effect of phospholipase D. Concentrate can be obtained by conducting the solvent extraction to the rough product, and then can be purified by solvent to obtain phosphatidylserine. The invention is characterized in that to separate the reaction substrate needs water three to ten times (w/v) of reaction substrate; and the separating temperature is ranged from 20 DEG C to 60 DEG C. In the system, the weight of the L-serine is two to ten times of the reaction substrate, and the weight of water used in the inorganic system is three to ten times(w/v) of reaction substrate. Ph value of the inorganic system can be adjusted between 4.5 and 6.0 by the buffer solution.

The present invention provides an enzymatic cycling assay for assessing the amount of homocysteine and/or cystathionine in a solution such as blood, blood derivatives, or urine. The assay comprises the steps of contacting the solution containing homocysteine and/or cystathionine to form a reaction mixture, with CBS, or a derivative thereof, L-serine, and CBL, or a derivative thereof, for a time period sufficient to catalyze the cyclical conversion of homocysteine form to cystathionine and the reconversion of cystathionine to homocysteine with the production of pyruvate and ammonia; determining the amount of homocysteine and/or ammonia present in the reaction mixture; and determining the amount of homocysteine and/or cystathionine present in the solution based on the amount of pyruvate and/or ammonia formed. Expression vectors and isolation procedures for CBS, or derivatives thereof, and CBL, or derivatives thereof, are also provided as well as test kits for carrying out the assay. In preferred embodiments, the assays can be conducted in 15 minutes or less, with a minimum of enzyme usage.

The invention belongs to the technical field of medicine and biology and particularly relates to a method for preparing L-tryptophan by enzymatic conversion. The method, of which L-tryptophan is prepared from mixed amino acids containing L-serine, comprises the following steps: mixing the high-activity genetic engineering bacteria of L-tryptophan synthetase or L-tryptophanase with the conversion solution of the mixed amino acid containing L-serine; carrying out the enzymatic reaction at the temperature of 30 to 45 DEG C; and then, separating the converted products by the isoelectric point crystallization method or the method combining isoelectric point crystallization and ion exchange resin to obtain high-purity L-tryptophan. The method solves the problems of the separation and overall development of L-serine in the mixed amino acids by obtaining L-serine products with wider applicable range and higher added value, therefore, the invention has the advantages of wide material availability, low price, convenient operation, short conversion time, low production cost and the like.

The invention relates to a preparation method of phosphatidylserine. The preparation method comprises the steps of carrying out enzymic catalytic reaction on natural lecithin and L-serine in the presence of phospholipase D enzyme liquid, and carrying out a simple purification process after the reaction, so as to obtain phosphatidylserine with the yield exceeding 60%. The preparation method has the beneficial effects that the operation is simple and convenient, the yield is high, the cost is low, the product quality is stable, and the process is environmentally friendly.

The invention relates to escherichia coli engineering bacteria for producing L-serine with high yield and a fermentation method for the engineering bacteria. The bacteria are escherichia coli Q3 with the collection number CGMCC 6213, and the genotype of the bacteria is MG1655 delta sdaA delta sdaB delta tdcG:: Cm. By using wild escherichia coli as a contrast, the culture results show that in a fermentation medium (containing 10 g/L of peptone, 5 g/L of yeast powder, 10 g/L of sodium chloride and 10 g/L of glucose), under the fermentation culture conditions that the pH value is 7.0, the temperature is 37+/-1 DEG C, the revolving speed of a shaker is 200+/-20 revolutions per minute and the fermentation time is 48+/-3 hours, the accumulation quantity of the L-serine produced by fermenting the engineering bacteria is improved by about 40 percent, a foundation is laid for constructing high-yield strains of phosphatidylserine, and the engineering bacteria have important application prospect and value.

The invention discloses a method for preparing phosphatidylserine under catalysis of immobilized phospholipase D. The method comprises the following steps: (1) with chitin as a vector and glutaraldehyde as a cross-linking reagent, immobilizing free phospholipase D to obtain immobilized enzyme of phospholipase D; (2) with the immobilized enzyme of the phospholipase D prepared in the step (1) as a catalyst, n-butyl acetate as an organic phase solvent, and 50mM of sodium acetate buffer solution of which the pH is 5.5 as a water phase solvent, reacting L-serine to react with soyabean lecithin at 20-60 DEG C according to the molar ratio of (10-100):1, thus obtaining phosphatidylserine; and at the end of reaction, filtering and recovering the phospholipase D for repeated use. By adopting the method disclosed by the invention, the ester transfer rate in the dual-phase catalytic system can be up to 78%, the immobilized enzyme can be repeatedly used, and the method is simple, easy to operate, and low in preparation cost.

The invention discloses a synthetic method of L-serine, which comprises the following steps: A) transforming the concentration of a substrate: adding the substrate, namely glycine and serine hydroxymethyltransferase accounting for 3%-8% by weight into a biological reactor; feeding 37% of formaldehyde water solution when the temperature is 40-50 DEG C and getting L-serine transformation liquid by transformation; B) purifying through an ultrafiltration membrane: purifying the L-serine transformation liquid in the A) step through the ultrafiltration membrane under the conditions that the temperature is 25-35 DEG C, the pressure at an inlet is 0.4-0.8MPa and the pressure at an outlet is 0.1-0.3MPa; C) performing adsorption and elution through ion-exchange resin: regulating the pH value of penetrating fluid in the B) step to 4.5-5.5, then exchanging the L-serine transformation liquid onto resin through the ion-exchange resin and further eluting with 0.8-1.5mol/L of hydrochloric acid; D) concentrating through a nanofiltration membrane: concentrating L-serine eluent in the step C) through the nanofiltration membrane under the conditions that the temperature is 25-35 DEG C, the pressure at the inlet is 0.4-0.8MPa and the pressure at the outlet is 0.1-0.3MPa; and getting an L-serine finished product after concentration. The synthetic method of the L-serine is simple in operation, short in production period, low in cost, high in yield and low in environmental protection pressure, and suitable for large-scale industrialized production.

The present invention includes a group of novel compounds that are demonstrated to potently and selectively inhibit HIV integrase (IN) activity in vitro and to potently inhibit HIV replication in live, cultured cells at non-toxic concentrations. The novel compounds disclosed include 2,3-di(3,4-dihydroxy-dihydroxydihydrocinnamoyl)-L-tartaric acid, 2,3-di-(3,4-dihydroxybenzoyl)-L-tartaric acid, 2,3-di-(3,4-dihydroxyphenylacetyl)-L-tartaric acid, 2,3-di-(3,4,5-trihydroxybenzoyl-L-tartaric acid, 2,3-dicaffeoyldiamidopropionic acid, 1,2,-dicaffeoyl-L-glyceric acid, bis,-3,4-dicaffeoyldiamidobenzoic acid, di-3,4-dihydroxybenzylidene succinic acid, di-3,4-dihydrodihydroxybenzylidine succinic acid, 2,3-dicaffeoyl-L-serine, bis-dicaffeoyl-L-isoserine and 1,4-dicaffeoyl-L-lysine. Tests of integrase inhibitors with 2′,3′-dideoxycytidine, zidovudine and nelfinavir (protease inhibitor) indicated a potent synergy against reverse transcriptase inhibitor resistant virus. The potential benefit from the addition of integrase inhibitors to combination drug therapies is significant.

The present invention discloses one kind of recombinant methylotrophic bacillus and its application. The recombinant methylotrophic bacillus MB202 is obtained through inserting glyA into the polyclonal site of pLAFR3 to obtain recombinant vector pLAFRg, and the subsequent three parent crossbreeding to introduce pLAFRg into methylotrophic bacillus MB200 to obtain the recombinant methylotrophic bacillus MB202. Through shaking table culture of MB202 at 32 deg.c in 50mM Tris-HCl culture medium with glycine in 10 mg/ml, methanol in 50 mg/ml, and biomass of 10<8>-10<9> CFU/ml, in pH 8.5 for 48 hr, L-serine yield may reach 11.5mg/ml; and through fermentation culture of MB202 at 32 deg.c for 12 hr, the activity of serine hydroxymethlase may reach 115 U. The recombinant methylotrophic bacillus MB202 has broad application foreground in producing L-serine and treating methanol waste water.

A 3-phosphoglycerate dehydrogenase (PGD) which exhibits a susceptibility to inhibition by serine which is reduced a as compared with that of an Escherichia coli wild-type PGD and which possesses an amino acid sequence which differs from the amino acid sequence of the Escherichia coli wild-type PGD (SEQ ID NO: 2) in that an amino acid apart from glycine is present at position 249 or an amino acid apart from threonine is present at position 372.

The invention provides an L-tyrosine preparation method through enzymatic conversion. The method comprises the following steps: 1, respectively culturing strains having the activities of serine deaminase and strains having the activities of tyrosine phenol-lyase in a culture medium; 2, mixing two cells of the serine deaminase and the tyrosine phenol-lyase with an L-serine-containing amino acid material liquid, adding an aqueous phenol solution having a concentration of 500g/L, pyridoxal phosphate having a concentration of 0.2g/L and a surfactant having a concentration of 0.01-1.0g/L, adjusting the pH value to 6-11 by using ammonia water having a volume percentage of 25%, and carrying out an enzymatic reaction for 6-35h; and 3, centrifuging the obtained conversion liquid for 15min in 4000r/min, collecting the obtained mixture, dissolving the mixture by using 200-7000ml of pure water, adding 10mol/L sodium hydroxide in a dropwise manner to adjust the pH value to 12-13, heating to 80DEG C while stirring, adjusting the pH value of the obtained filtrate to 6 by using 6mol/L hydrochloric acid, and drying to obtain required L-tyrosine.

The invention discloses monkey-bread tree moisturizing cream. The monkey-bread tree moistening cream comprises the following ingredients in parts by weight: 3-7 parts of ANANSODNIA DIGITATA seed oil, 2-6 parts of diacetyl tartaric acid ester of mono-and diglycerides, 10-20 parts of lanolin, 0.1-0.5 parts of L-serine, 8-12 parts of a moisturizing agent, and 50-60 parts of water. The monkey-bread tree moisturizing cream is natural and mild, nearly has no irritation, can be used for nourishing the skin and moisturizing for a long time, has better water supplementing and moisturizing effects on dry skin, sensitive skin and the like, and can be used for effectively improving the skin color and increasing the skin resiliency.

The invention provides a strategy combining metabolic engineering reconstruction with a fermentation process. On the one hand, a metabolic flow is changed to flow from a glycolysis route to an L-serine synthetic route by virtue of a metabolic engineering means, so that the sugar-acid conversion efficiency of L-serine is improved; and on the other hand, nutritional ingredients are added to meet requirements of corynebacterium glutamicum on nutrient substances after metabolic reconstruction, so that the problem of slow growth of thalli is solved, and the production strength of L-serine is improved.

The invention belongs to the field of chemical synthesis, and concretely relates to a synthetic method for L-selenocysteine. The method comprises the following steps: a, chloridizing L-serine hydrochloride to obtain 3-chloro-L-alanine hydrochloride; b, performing seleno-reaction of 3-chloro-L-alanine hydrochloride prepared by step a under alkaline condition to obtain L-selenocystine; and c, performing reduction reaction of L-selenocystine to obtain L-selenocysteine. The method has simple steps, high yield, low cost, and good application prospect.