90 results about "L-asparagine" patented technology

The invention relates to a macropore carrier 'synchronization method' covalent crosslinking-immobilized papain polymer and a method. In the papain polymer, a papain is embedded in the pore canal of a carrier the aperture of which is more than 0.5mu m; an inorganic macroporous material or an organic macroporous material the surface of which is provided with hydroxyl is taken as an immobilized enzyme carrier; synchronous complementation of the formation of the crosslinking papain polymer and the covalent connection of the crosslinking papain polymer and the macroporous carrier is finally realized through amino-group modification, enzyme adsorption, enzyme precipitation and synchronous crosslinking on the surface of the carrier; the enzyme carrying amout of the immobilized enzyme is higher than that of the immobilized enzyme of a common carrier; the enzyme leakage caused by applications of the macroporous carrier is avoided by adopting a covalent fixed method; the carrier shape can be adjusted according to the actual requirements; and the optimum catalysis temperature, pH value, solvent and heat stability are obviously improved. The papain polymer provided by the invention can be applied to other proteases, lipase, amylase, glucose isomerase, penicillin, acylase, pectinase, oxidase, L-asparaginase, aspartase and peroxidase and the like.

The invention discloses an L-asparaginase mutant with the improved enzyme activity and a construction method thereof, and belongs to the field of gene engineering. According to the L-asparaginase mutant, on the basis of amino acid shown in the SEQ ID NO.2, the 107th glycine is mutated into aspartic acid. The obtained mutant is expressed in bacillus subtilis, fermentation is performed in a shake flask for 24 h and then the enzyme activity is 961 U/mL; the enzyme activity of the mutant is improved by 80%, the appetency of a substrate is decreased by 50% compared with protoenzyme, the catalytic efficiency is improved by 84%, and meanwhile the specific enzyme activity is improved by 83%. According to the L-asparaginase mutant, it is shown that the 107th amino acid residue has a great influence on the enzyme catalytic action, a certain foundation is provided for research on the enzyme catalytic mechanism, and the enzyme industrial application potential is improved.

The invention synthesizes a type of liver targeted, biodegradable high molecular MRI contrast medium with alpha,beta- poly [(2-aminoethyl) - L-asparagine] as fundamental chain, galactose as target gene, diethylenetriamine pentaacetic acid or L-tyrosine methyl ester derivatives as Gd3+ ligand. The contrast agent is less toxic, biocompatible, and has good relaxation rate than low molecular business contrast medium. Animal experiments showed that in liver organizations its enhancing effect is three times better than commercial and low molecular contrast medium (gadolinium sprayed acid cyelophosphate); the residence time in liver is more than 24 hours, which is 18 hours longer than low molecular business contrast medium. The feature is that Zeta potential for the contrast medium is negative and less than -10mV. We can achieve the MRI visible, the liver targeted, core-shell nanogene vector system with it as a gene vector system shell structure.

In its several embodiments, this invention discloses a pharmaceutical formulation comprising at least one antineoplastic agent or a pharmaceutically acceptable salt thereof, and at least one dissolution enhancing agent sufficient to substantially dissolve said at least one antineoplastic agent in at least one aqueous diluent, wherein said dissolution enhancing agent is urea, L-histidine, L-threonine, L-asparagine, L-serine, L-glutamine or mixtures thereof; a lyophilized powder comprising said pharmaceutical formulation, and articles of manufacture thereof.

The invention provides deimmunized mutant proteins having reduced immunogenicity while exhibiting substantially the same or greater biological activity as the proteins of interst from which they are derived, as exemplified by mutant L-asparaginase that comprises amino acid substitutions compared to wild type L-asparaginase. The invention further provides methods for screening mutant deimmunized proteins that have substantially the same or greater biological activity as a protein of interest, and methods for reducing immunogenicity, without substantially reducing biological activity, of a protein of interest.

The invention's compositions and methods are useful in, for example, therapeutic applications by minimizing adverse immune responses by the host mammalian subjects to the protein of interest. Thus, the invention further provides methods for treating disease comprising administering to a subject a therapeutically effective amount of a pharmaceutical composition comprising at least one of the mutant deimmunized proteins produced by the invention's methods.

The invention discloses a method for improving secretory expression of L-asparaginase, and belongs to the field of genetic engineering. According to the method, by fusing a pelB signal peptide at an N terminal of asparaginase, the enzyme activity of the extracellular asparaginase of a recombinant bacterium is increased by 20 times, and further through coexpression of lepB signal peptidase, the enzyme activity of the asparaginase can be increased by 1.45 times on the above basis. The enzyme-producing capacity of a modified bacterial strain is significantly improved; the method is more suitable for industrial application; by the method, the production cost can be reduced and the production efficiency can be improved.

The invention discloses an environment-friendly mixed feed for pigs and a preparation method thereof. The environment-friendly mixed feed for pigs is prepared from the following ingredients in part by weight: the environment-friendly mixed feed is prepared from corn, bean pulp, wheat bran, DDGS (distillers dried grains with soluble), acyl hydroxylation emulsified oil powder, calcium hydrogen phosphate, mountain flour, enzyme preparation, calcium propionate, citric acid, lysine, methionine, threonine and pre-mixture; and functional additives in the premixture comprise histidine, arginine, leucine, valine, corynebacterium glutamicum, L-asparaginate-L-phenylalanine methyl ester, spiral seaweed, glucanase, bacillus subtilis and sodium butyrate. According to the feed, engineering bacteria is utilized to generate glutamic acid through fermentation in an intestinal tract of the pig, the additional amino acids in the feed are balanced, all amino acids are induced to be combined in the small intestine in an ideal amino acid mode to be absorbed, the protein level of the feed and the carbon-nitrogen emission are reduced, a part of amino acids are promoted to be deposited in pork, the pork flavor is improved and the pork quality is improved.

The invention concerns a glycosylasparaginase polypeptide with L-asparaginase activity or its precursor for use in the treatment or prevention of cancers or inflammatory diseases. The invention concerns also a novel pharmaceutical composition comprising either i) the glycosylasparaginase polypeptide or its precursor, or ii) an expression vector encompassing a nucleic acid sequence encoding the glycosylasparaginase polypeptide or its precursor for use in the treatment or prevention of cancers or inflammatory diseases.

The invention relates to synthesis and a crystal form-transforming method of taltirelin. An intermediate S-1-methyl-4,5-dihydro-orotic acid is synthesized by using L-asparagine as a starting material and through Friedel-Crafts acylation, esterification, methylation and hydrogenation; His(Trt)-Pro-NH2 is prepared by reacting Fmoc-His(Trt)-OH with Pro-NH2 and deprotecting; a taltirelin salt crude product is obtained by carrying out condensation reaction on S-1-methyl-4,5-dihydro-orotic acid and His(Trt)-Pro-NH2, adding trifluoroacetic acid, stirring, adding a crystallization solvent, stirring, suction filtering and washing; taltirelin is obtained by purifying, desalting and freeze-drying; and beta-taltirelin is obtained by adding taltirelin into pure water for dissolution and crystallization, adding methanol, stirring, crystallizing and suction-filtering. Racemization of a final product in medium test amplification is effectively controlled in the reaction processes; product purity is high; production security is guaranteed; and the synthesis and crystal form-transforming method are suitable for large-scale amplified production.

The invention relates to a L-asparaginase variant with increased activity, and is a variant of escherichia coli wild type L-asparaginase shown in a SEQ ID NO:3, and the variant comprises an one or a plurality of amino acid substituted amino acid sequence on 48th site, 49th site, 152nd and 283rd by corresponding to a SEQ ID NO:3. The invention also provides the separated nucleic acid containing the nucleotide sequence which codes the L-asparaginase variant, a recombinant expression construct containing the nucleic acid and a recombinant host cell containing the expression construct. In addition, the invention also provides a method for generating the L-asparaginase variant. The invention also provides a pharmaceutical composition used for treating tumor containing the L-asparaginase variant.

The invention discloses a bismuth oxide photocatalyst, a preparation method, and applications thereof. The preparation method comprises the following steps: dissolving bismuth-containing compounds and L-asparagine in water to obtain a uniform solution, then placing the solution in a space with a constant temperature of 80 to 160 DEG C for 4 to 8 hours, cooling, then washing and drying the precipitate, and finally burning the precipitate at a temperature of 320 to 440 DEG C for 1 to 4 hours to obtain the bismuth oxide photocatalyst. In the provided preparation method, the bismuth-containing compounds and L-asparagine carry out reactions at a low temperature under a normal pressure to generate a precursor, and after the burning, the precursor as a self-sacrificing template is degraded and converted into a nano flower-shaped beta-phase bismuth oxide visible-light photocatalyst. The nano flower-shaped beta-phase bismuth oxide has the advantages of higher uniformity, fine granularity, narrow particle size distribution, and certain morphology. The average particle size of the bismuth oxide grains is 50 nanometers, and the nano three-dimensional flower-shaped structure composed of the bismuth oxide grains has an average diameter of 300 to 600 nanometers. The bismuth oxide photocatalyst can be applied to catalytic degradation of organic pollutants, and can also be used in the fields such as optoelectronic equipment, industrial catalysts, and the like.

The invention relates to novel engineering bacteria for producing L-asparaginaseII. An extracellular expression product of the engineering bacteria has L-asparaginaseIIprotein activity. The invention also discloses a construction method and fermentation culture conditions of the engineering bacteria, wherein recombinant plasmids pET-ASP invert colon bacillus BL21 to obtain the engineering bacteria; and the structure of the recombinant plasmids pET-ASP is shown in figure 1. The recombinant engineering bacteria are obtained by connecting the L-asparaginase II genes on expression plasmids pET22b to obtain the recombinant plasmids pET-ASP and then using the recombinant plasmids pET-ASP to invert the colon bacillus BL21. The L-asparaginase II can be produced massively by carrying out fermentation culture on the engineering bacteria. And the engineering bacteria has wide raw material source, low cost, and few separation and purification steps and high yield of the products in the fermentation liquor.

The present invention provides a method of using a fertilizer, comprising an amino acid selected from the group of L-glutamine, L-asparagine and L-arginine as major nitrogen source, optionally together with inorganic nitrogen and/or a suitable preservative, for stimulating root growth, inducing more fine roots, increase the number of root tips and/or for stimulating mycorrhiza development.

The invention discloses L-asparaginase as well as an encoding gene and application thereof. A protein disclosed by the invention is shown in the following formula (1) or (2): (1) the protein is a protein shown in SEQ ID No.2; and (2), the protein is a protein which is obtained through substitution and/or deficiency and/or addition of one or more amino acid residues on an amino acid sequence shown in SEQ ID No.2 and has the same function. The L-asparaginase disclosed by the invention is suitable for being used as a food additive applied to bakery products so that the production amount of acrylamide as a cancerogen in the product is reduced, and is also suitable for being used as a medicine applied to adjuvant therapy of leucocythemia.

The invention discloses a human skin cell growth solution. The human skin cell growth solution is prepared from the following components of L-arginine, L-asparagine, L-aspartate, L-cystine dihydrochloride, L-glutamic acid, glycine, L-histidine, L-hydroxyproline, L-leucine, L-lysine hydrochloride, L-methionine, L-phenylalanine, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine, L-glutamine, succinic acid, sodium pyruvate, para aminobenzoic acid, calcium nitrate, potassium nitrate, ammonium nitrate, anhydrous magnesium sulfate, anhydrous sodium dihydrogen phosphate, sodium bicarbonate, potassium chloride, sodium chloride and magnesium chloride. The human skin cell growth solution has the advantages that the nutrients required by growth of cells of basal layers are provided, the newborning of surface cells is promoted, and the skin moisturizing, nourishing and compactness effects are realized; the proliferation of collagen is promoted, the dermis is thickened, the skin elasticity is restored, the aging is delayed, the market prospect is broad, and the human skin cell growth solution is suitable for being greatly popularized.

The invention discloses a preparation method of D-asparagine, which is characterized in that the method comprises the following steps: (1) allowing L-asparagine to react with phthalic anhydride at 130 DEG C-180 DEG C so as to generate phthaloyl-L-aspartic acid; (2) allowing the phthaloyl-L- asparagine obtained in step (1) to perform reflux reaction with acetic anhydride and a racemization reagentfor 20-60 min so as to generate phthaloyl-DL-aspartic anhydride; (3) allowing the phthaloyl-DL- aspartic anhydride obtained in step (2) to react with an ammonia tetrahydrofuran solution so as to obtain phthaloyl-DL-asparagine; (4) allowing the phthaloyl-DL-asparagine obtained in step (3) to react with hydrazine hydrate to remove the phthaloyl group so as to obtain the product of DL-asparagine; (5) specifically hydrolyzing L-asparagine in the DL-asparagine obtained in step (4) by microbial L-asparaginase for separation so as to obtain D-asparagine and L-asparagine.

The invention discloses a recombinant escherichia coli efficiently transforming fumaric acid into L-asparagine as well as a construction method and an application thereof. Fumarase encoding genes fumA, fumB, fumC in an ammonium-tolerant escherichia coli BEW308 are inactivated, and then L-aspartase encoding and L-asparaginase encoding genes are inserted into the positions of the fumarase encoding fumAC genes, thereby obtaining the recombinant escherichia coli having no malic acid by product, less L-aspartic acid accumulated, and a major product L-asparagine. The invention also discloses a construction method and an application of the bacterial strain. The recombinant escherichia coli can realize constitutive high-activity expression of L-aspartase and L-asparaginase, and ultimately achieve transformation of fumaric acid into L-asparagine.