187 results about "Glutaminase" patented technology

The invention provides bacillus amyloliquefaciens as well as a construction method and application thereof. Wherein the bacillus amyloliquefaciens is the bacillus amyloliquefaciens of which the stress response transcription factor glcR gene is knocked out, and the bacillus amyloliquefaciens is a bacillus amyloliquefaciens of which the stress response transcription factor glcR gene is knocked out; the nucleotide sequence of the glcR gene is as shown in SEQ ID NO: 1. By knocking out a stress response transcription factor glcR gene in bacillus amyloliquefaciens, the level of glutaminase expression by using the bacillus amyloliquefaciens can be enhanced, the enzyme activity of the glutaminase obtained by expression is relatively high, and the activity of the enzyme can be further improved by using the modified strain; powerful technical support is provided for commercialized production of glutaminase, and great economic benefits and application prospects are achieved.

The invention provides a genetically engineered bacterium and a construction method of the genetically engineered bacterium, and the genetically engineered bacterium is characterized in that a green fluorescent protein sfGFP is used for mediating protein glutaminase, PG (protein glutaminase), PGF (protein glutaminase), PGF, PGF, PGF, PGF, PGF, PGF, PGF, PGF, PGF, PGF, PGF, PGF, PGF, PGF, PGF, PGF and PGF; eC 3.5. 1.44) is efficiently secreted and expressed in engineering bacteria, and belongs to the technical field of biological engineering. The method comprises the following steps: an obtained sfGFP gene is derived from an NCBI database (GenBank numbering: CP035486.1), an obtained PG zymogen gene PP (Propeptide-Protein glutaminase) is derived from a Chryseobacterium prion prgA gene (GenBank numbering: AB046594.1) in the NCBI database, a recombinant plasmid pHT01 / sfGFP-PP is introduced into bacillus subtilis WB800N to obtain an engineering bacterium, extracellular secretion expression of PP is realized, the sfGFP-PP is activated by trypsin to obtain PG, and the PG is subjected to enzyme activation to obtain the recombinant bacillus subtilis. The expression quantity and the secretion efficiency of the PG in the bacillus subtilis are greatly improved. The recombinant PG produced by the method can generate 23.5 U / mL enzymatic activity under activation of trypsin, can be used for improving protein functional characteristics, and has relatively high industrial production and application values.

The invention provides an enzymolysis preparation method of a milk-derived taste enhancing peptide, which comprises the following steps: carrying out enzymolysis on a liquid dairy product by using flavourzyme and glutaminase, and then carrying out enzyme deactivation to obtain an enzyme-deactivated product; carrying out acidification centrifugation and ultrafiltration on the enzyme-deactivated product, and freeze-drying the separated effluent to obtain freeze-dried powder; and loading the freeze-dried powder, and separating by a glucose gel column. The product disclosed by the invention does not generate bitter taste, and compared with a sample which is not subjected to enzymolysis, the flavor level of an original skimmed milk product is enriched, and the sample subjected to enzymolysis has the mellow taste of caramel and frankincense. The method comprises the following steps: separating milk-derived taste active peptides from milk-derived taste active peptides, predicting delicate flavor, anti-oxidation and anti-inflammatory activity and ACE blood pressure lowering functional activity of separated peptide liquid through a model, performing taste verification on the peptides predicted to have taste activity through Fmoc solid-phase synthesis, and performing sensory verification on the milk-derived taste active peptides LSFD, EDIKQME, IKQMEAE and TEDELQDK after synthesis, so that the milk-derived taste active peptides are obtained for the first time and are subjected to sensory verification.

The invention relates to the technical field of pharmaceutical preparations, in particular to a preparation process of carbon dots for killing helicobacter pylori and application of the carbon dots in oral pharmaceutical preparations. The preparation method comprises the following steps: mixing microcrystalline cellulose and glycerol, freezing and crushing at an ultralow temperature, and selectively hydrolyzing by combining citric acid-malic acid mixed acid liquor to efficiently prepare a high-crystallinity cellulose nanocrystal template; the controllable synthesis of the carbon dots is realized by utilizing the hydrogen-bond interaction of hydroxyl / carboxyl on the surface of the cellulose nanocrystal and the nitrogen doping effect in the polymerization and carbonization process of citric acid and urea. Besides, when a sodium alginate-chitosan double-layer structure is constructed, carbon dots are introduced into the inner layer to endow the inner layer with special performance, a protein-polysaccharide network is formed on the outer layer through transglutaminase enzymatic crosslinking, and the oxidation resistance and mechanical strength are enhanced through secondary curing of tea polyphenol. According to the invention, food-grade raw materials are used for realizing high-efficiency antibiosis, the oral preparation safety specification is met, and the clinical transformation potential is realized.

The invention discloses a gelatin-hyaluronic acid injectable hydrogel drug-carrying nanoparticle composite material as well as a preparation method and application thereof, relates to the technical field of biomedicine, and solves the problems that in the prior art, existing drugs for treating cartilage related diseases are difficult to deliver; the chronic inflammatory response in the articular cavity cannot be effectively controlled and cartilage cells cannot be protected at the same time, so that the application effect of the medicine is limited. The preparation method disclosed by the invention comprises the following steps: S1, obtaining a carnosine modified hyaluronic acid derivative Car-HA; s2, preparing nano particles (FNPs) loaded with fenofibrate; and S3, mixing the gelatin solution containing the FNPs with a Car-HA solution, adding transglutaminase into the mixed system, and carrying out an enzymatic cross-linking reaction to form the hydrogel FNPs-GelHA with a stable network structure. The CarHA and FNPs synergistic hydrogel strategy provided by the invention has good structural adjustability and drug adaptability, is suitable for delivery of various anti-inflammatory, anti-oxidation and cartilage repair drugs, and can be widely applied to local precise treatment of cartilage related diseases.

The invention relates to the technical field of food processing, in particular to antioxidant nano collagen peptide powder and a preparation method thereof.The antioxidant nano collagen peptide powder is prepared by forming antioxidant micelles wrapping collagen peptide through collagen peptide liquid and a complex antioxidant, loading the antioxidant micelles on a porous carrier and then conducting cross-linking through transglutaminase; tea polyphenol and whey protein are covalently combined to prepare a composite antioxidant, rapid free radical neutralization, lactoferrin inhibition of an oxidation source and synergistic effect of collagen peptide self-antioxidant groups are provided, multistage barrier design is combined, oxygen diffusion is isolated through a micelle hydrophobic core, and the contact area of micelles and the outside is reduced through physical adsorption of a porous carrier, so that the anti-oxidation effect of the collagen peptide is improved. Finally, the micelles are fixed in the carrier by utilizing an enzyme cross-linked network, so that the antioxidant nano collagen peptide powder has efficient and long-acting antioxidant capacity.

The invention discloses an enzymolysis preparation process of wood frog skin micromolecule III type collagen peptide. The enzymolysis preparation process comprises the following steps: mixing defatted wood frog skin powder with water, and pretreating; adding a papain-neutral protease-glutamine protease hydrolysis system into the pretreated mixed solution, continuously hydrolyzing, performing centrifugal treatment after the hydrolysis is completed, heating supernate, adding alkaline protease into the supernate for hydrolysis and enzyme inactivation, and performing centrifugal treatment to obtain clear liquid rich in collagen peptide; carrying out multistage membrane separation coupling chromatography purification treatment and low-temperature vacuum concentration treatment on the clear liquid rich in collagen peptide to obtain a concentrated solution; and mixing the concentrated solution with a trehalose-hyaluronic acid composite wall material, and performing spray drying to obtain the collagen peptide nanocapsule. Efficient preparation and function enhancement of the wood frog skin type III collagen peptide can be achieved, and the prepared collagen peptide has the purity larger than or equal to 99.5% and the activity retention rate larger than 98% and is excellent in heat stability and moisturizing performance.

Disclosed herein are methods of treating a tumor or cancer in a subject whose tumor or cancer cells express low levels of asparagine synthetase (ASNS), and compounds and compositions useful in such treatment. Also disclosed herein are methods of evaluating whether to administer a compound that inhibits glutathione production or a glutaminase inhibitor to a subject with a tumor or cancer.

The invention provides a composition for reducing uric acid and relieving gout and a preparation method thereof, and relates to the technical field of products for reducing uric acid and relieving gout. The composition comprises the following raw materials: 18-24 parts of phellinus igniarius, 9-13 parts of sunflower disc small molecule peptide extract, 3-7 parts of corn stigma, 4-6 parts of poria cocos, 2-5 parts of pawpaw, 3-6 parts of liquorice, 2-5 parts of astragalus extract and 3-6 parts of lettuce extract. The preparation method of the sunflower disc small-molecule peptide extract comprises the following steps: carrying out enzymolysis on sunflower disc powder twice, carrying out membrane filtration to obtain a sunflower disc small-molecule peptide solution, reacting the sunflower disc small-molecule peptide solution with chitosan oligosaccharide and transglutaminase, and carrying out freeze drying to obtain the sunflower disc small-molecule peptide extract. Through the proper raw material composition and proportion, the metabolic function can be effectively regulated to promote excretion of uric acid, so that the content of xanthine oxidase and adenosine deaminase in the liver is obviously reduced, the uric acid level is effectively reduced, the intestinal probiotic structure can be stabilized, the immunity is enhanced, the kidney is protected, and the good effects of reducing uric acid and relieving gout are achieved.

The invention relates to the field of biomedical application of inorganic materials, in particular to application of lanthanum carbonate in preparation of a medicine for treating hepatic encephalopathy. According to the application of lanthanum carbonate in preparation of the medicine for treating hepatic encephalopathy, the medicine comprises lanthanum carbonate and pharmaceutically acceptable auxiliary materials, the lanthanum carbonate comprises any one or more of lanthanum carbonate hydrate and basic lanthanum carbonate, the medicine is ground and then mixed with food to prepare a medicine mixture, and the medicine mixture is prepared into the medicine for treating hepatic encephalopathy. The mass ratio of the lanthanum carbonate in the medicine mixture is 1-10%. According to the application, the blood ammonia is reduced based on the glutaminase, the hepatic encephalopathy is reversed by reducing the blood ammonia and systemic inflammation, and the liver function is recovered by regulating the inflammation, so that the hepatic encephalopathy is favorably cured, a good treatment effect is shown, and a new candidate medicine is provided for clinically treating the hepatic encephalopathy.

The invention discloses a preparation method and application of a myofibrillar protein emulsion based on enzymatic modification. According to the technology, a myofibrillar protein aqueous suspension is subjected to enzymatic deamidation and glycosylation reaction through protein glutaminase and glucan, a protein-polysaccharide compound with good emulsifying performance is constructed, soybean oil serves as an oil phase, and emulsion systems with different oil phase volume fractions are constructed through a controllable homogenizing technology. The obtained emulsion has the characteristics of natural degradability, excellent rheological property, uniform particle size distribution, long-term physical stability and the like. Compared with a traditional chemical modification technology, the technology adopts a whole bio-based raw material combined enzyme method green technology, the problems of organic solvent residues and the like are effectively solved, and the production cost is reduced while the product safety is ensured. The emulsion has remarkable application advantages in the fields of functional food active ingredient delivery, drug controlled release carriers, cosmetic transdermal absorption systems and the like, and a new thought is provided for development of a biomacromolecule-based delivery system.

The invention belongs to the technical field of protein processing, and particularly relates to modified beta-lactoglobulin as well as a preparation method and application thereof. The modified beta-lactoglobulin is a composite modified product which is obtained by performing a papain hydrolysis treatment process on beta-lactoglobulin to obtain a hydrolysate and then performing glycosylation modification on the hydrolysate by adopting chitosan oligosaccharide and transglutaminase. The product has significantly improved oxidation resistance, emulsifying properties and foaming activity, and is suitable as a food processing ingredient, such as an antioxidant, an emulsifier or a foaming agent.

The invention relates to a flame-retardant skin-friendly polyurethane sponge with in-situ reaction and bio-enzyme catalysis synergism. The water-based polyurethane foam is prepared from the following components: polyether polyol, diphenylmethane diisocyanate or toluene diisocynate, a chain extender, a high-efficiency foam stabilizer, a high-efficiency composite catalyst, water and ethanolamine phosphate, ethanolamine phosphate is added into water in advance, and then all the raw materials are mixed for polymerization foaming; after curing, spraying a spraying liquid consisting of phosphoethanolamine, regenerated protein and transglutaminase to generate a nano protein film, and synchronously performing vacuum suction to keep sponge pores unblocked. The preparation method has the advantages that a small amount of ethanolamine phosphate is added before polymerization foaming to serve as a phosphorus-nitrogen synergistic flame retardant and also serve as a catalytic cross-linking agent to participate in a reaction during polymerization, biological enzyme is added for catalysis after curing is finished, and the skin-friendly PU sponge with excellent flame retardance is prepared through in-situ polymerization reaction and biological enzyme enzymatic polymerization cooperation, and the sponge performance is not affected; the raw materials of the flame retardant come from biomass products and are environment-friendly and safe.

The invention relates to a high-yield protein glutaminase Chryseobacterium prion strain and a preparation method thereof. The strain is obtained by carrying out ARTP and NTG compound mutagenesis treatment on an original strain of Chryseobacterium prion and carrying out high-throughput screening on the strain subjected to the compound mutagenesis treatment. The strain is preserved in the China Center for Type Culture Collection, and the preservation number is CCTCC M 20251792. The invention also relates to a method for preparing protein glutaminase by using the strain of the invention. The enzyme activity of the protein glutaminase of the strain is 6 times that of an original strain, and the production efficiency of the protein glutaminase can be remarkably improved.

The present invention discloses an engineered protein glutaminase mutant and its method for active secretion expression in Pichia pastoris. The present invention successfully improves the catalytic activity of FBPG through surface charge modification, and the specific activity of mutant F3 reaches 9.43 times that of the wild type. The secreted expression of FBPG is achieved in Pichia pastoris, and under the regulation of the P DH promoter, the active expression of FBPG is achieved by introducing the Kex2 cleavage site. After overexpressing the transcription factor Sko1, the yield of active FBPG reaches 2610 U / L in a 7 L bioreactor, providing a feasible technical solution for the application of FBPG in the food industry, and also providing new ideas and methods for the active expression of similar enzymes.

The invention provides bacillus licheniformis for high-yield protein glutaminase as well as a construction method and application of the bacillus licheniformis, a target strain is obtained by knocking out an alkaline protease gene aprE and extracellular protease genes bpr, epr, vpr or wpr and heterologously expressing the protein glutaminase gene, an EPE strain is optimal in expression, PG enzyme activity reaches 0.358 U / mL and is improved by 3.55 times compared with that of a wild type, and the bacillus licheniformis has the advantages that the bacillus licheniformis is high in yield and high in protein glutaminase yield. In addition, the growth condition of each mutant strain is not obviously abnormal, and the growth speed is obviously increased. It is fully proved that the expression level of the heterologous protein PG can be remarkably improved by targeted knockout of the extracellular protease gene of the bacillus licheniformis, and a theoretical basis is laid for construction of an efficient protein expression host. The invention not only provides a new scheme for high-efficiency expression of PG, but also provides important reference for expression optimization of heterologous proteins of other gram-positive bacteria, and shows a wide industrial application prospect.

The invention relates to the technical field of bioengineering, in particular to an enzyme-mediator reactor, a preparation method thereof and application of the enzyme-mediator reactor in PFOA defluorination. The preparation method comprises the following steps: preparing a cyclodextrin-polyethylene glycol premixed transparent solution, wherein the cyclodextrin-polyethylene glycol premixed transparent solution comprises cyclodextrin and amino polyethylene glycol; n-carbobenzoxy-L-glutamyl glycine and transglutaminase are added into the cyclodextrin-polyethylene glycol premixed transparent solution for an end capping reaction, a reaction product is subjected to impurity removal and drying, and a cyclodextrin-polyethylene glycol composite material is obtained; enzyme, syringaldehyde and the cyclodextrin-polyethylene glycol composite material are subjected to self-assembly crosslinking in a buffer solution, and the enzyme-mediator reactor is obtained. The prepared enzyme-mediator reactor has the green and environment-friendly characteristics while maintaining the high defluorination rate, and a novel biological catalysis solution is provided for treatment of persistent pollutants.

The invention discloses an application of a small molecule compound CB-839 in preparation of a medicine for treating diabetic kidney diseases. The treatment of the diabetic kidney disease means that the renal function and the kidney injury of the diabetic kidney disease are obviously improved by the CB-839 (C26H24F3N7O3S). The CB-839 is a glutaminase 1 (GLS1) inhibitor, and can prevent in-vivo glutamine decomposition by inhibiting the activity of glutamine decomposition enzyme so as to maintain the in-vivo concentration of the CB-839. In addition, the CB-839 shows antitumor activity in animal experiments. Experimental results show that the CB-839 can inhibit glutamine decomposition, so that the purpose of improving prognosis of the diabetic kidney disease is achieved.

The invention provides a preparation method and application of myofibrillar protein hydrosol, and the method comprises the following steps: uniformly dispersing myofibrillar protein in water to obtain a myofibrillar protein suspension, mixing the myofibrillar protein suspension with protein glutaminase to obtain a mixed solution A, mixing the mixed solution A with a glucan aqueous solution to carry out glycosylation reaction to obtain a mixed solution B, and carrying out freeze drying to obtain the myofibrillar protein hydrosol. And cooling in an ice-water bath, and storing at 4 DEG C to obtain the myofibrillar protein hydrosol. The myofibrillar protein hydrosol is used for preparing protein beverages and nasal feeding nutrient solutions. The method for preparing the myofibrillar protein hydrosol with excellent dispersity and storage stability at lower production cost under the condition that professional large-scale instruments and equipment are not needed is used for preparing protein beverages and nasal feeding nutrient solutions.

The invention discloses a preparation method and application of a high-strength, mildew-proof and low-cost cottonseed meal protein adhesive. The preparation method comprises the following steps: compounding L-lysine and 4-carboxyphenylboronic acid through a coupling reaction to prepare lysine borate, adding the prepared lysine borate into the cottonseed meal protein adhesive, adding a proper amount of transglutaminase, and uniformly stirring to obtain the novel high-strength, mildew-proof and low-cost cottonseed meal protein adhesive based on the skin bionic strategy. The innovation points of the invention are as follows: by simulating a peptide bond between protein and polysaccharide in skin and forming a compact cross-linked layer through dehydration condensation reaction, using transglutaminase to construct a grain-lysine isopeptide bond, and introducing boric acid to form a covalent boron-oxygen-six-ring structure, a dual cross-linked network is constructed. The cottonseed meal protein adhesive has the advantages that the bonding strength, mildew resistance and other properties of the cottonseed meal protein adhesive can be remarkably improved only by using trace transglutaminase and boron oxygen six-ring as cross-linking agents, and the preparation cost of the adhesive is reduced.

The invention discloses a non-phosphorus green composite water holding agent for improving the quality of chicken feet and an application method of the non-phosphorus green composite water holding agent, and belongs to the technical field of food processing. The raw materials of the non-phosphorus green composite water-holding agent comprise a dissociation water-holding agent and a crosslinking water-holding agent, and sodium bicarbonate provides an alkaline environment, so that protein is negatively charged, and electrostatic repulsion among carboxyl groups is increased. And collagen can be dissociated, the water binding capacity of meat is increased, the tenderness of the meat is improved, the bulkiness of the meat is increased, the protein network structure of the treated chicken feet is looser, and the water binding capacity is remarkably enhanced. Transglutaminase can catalyze cross-linking of glutamine and lysine in protein to form a tight three-dimensional network to physically wrap moisture; the protein structure can be stretched, hydrophilic groups are exposed, and the binding force with water is enhanced; meanwhile, combination of muscle fibers and collagen is strengthened, and the structure is stabilized. In addition, water loss caused by high temperature, freezing and the like in processing can be resisted, the succulent property and elasticity of meat are improved, and therefore the water-retaining property is improved.

The invention discloses a temperature-sensitive gel preparation containing a glutaminase inhibitor as well as a preparation method and application of the temperature-sensitive gel preparation, and belongs to the technical field of biological medicines. The temperature-sensitive gel preparation comprises outer-layer gel and inner-layer gel, the inner-layer gel is coated with the outer-layer gel, the outer-layer gel accounts for 40-75% of the total mass of the temperature-sensitive gel preparation, and the inner-layer gel accounts for 25-60% of the total mass of the temperature-sensitive gel preparation; the outer-layer gel is prepared from the following raw materials: an outer-layer gel matrix, a glutaminase inhibitor, a photosensitizer and a stabilizer; the raw materials of the inner-layer gel comprise an inner-layer gel matrix and an immune checkpoint inhibitor. According to the temperature-sensitive gel preparation, through photo-thermal control, the glutaminase inhibitor is firstly released to relieve the immunosuppression state, then the immune checkpoint inhibitor is released to kill tumors, and the glutaminase inhibitor and the immune checkpoint inhibitor act synergistically, so that efficient anti-tumor immunotherapy is achieved.

The invention relates to an efficient preparation and activation method of natural protein glutaminase, and belongs to the technical field of biology. The invention provides a method for preparing and activating natural protein glutaminase, which comprises the following steps of: expressing fusion protein consisting of super-folded green fluorescent protein, a protein glutaminase propeptide region, intein and a protein glutaminase mature region in bacillus subtilis; extracellular expression of fusion protein is guided by super-folded green fluorescent protein, the fusion protein is spontaneously cut by intein Mxe GyrA, activated protein glutaminase is obtained, the sequence of the activated protein glutaminase is completely consistent with that of natural protein glutaminase, the highest enzyme activity reaches 52.3 U / mL, and the activity of the protein glutaminase is remarkably improved. The problem that the mature enzyme sequence is changed due to poor protease activation specificity in the prior art is solved, a brand new thought and tool are provided for efficient preparation and activation of protein glutaminase, and the method has wide application prospects.

The invention belongs to the technical field of gene therapy and biological medicine, and particularly provides application of leucine in preparation of a medicine for preventing and / or treating aortic aneurysm. The leucine is independently used or is combined with other medicines for preventing and / or treating aortic aneurysm. The activity of GLUD1 is enhanced through leucine, so that conversion of Glu to alpha-KG is promoted, degradation of Glu is promoted, namely, the Glu level is reduced by enhancing degradation of Glu, and aortic aneurysm is improved. In a Glu metabolic network, Gln can be converted into Glu under the action of glutaminase 1 (GLS1), so that the generation of Glu is inhibited by inhibiting the activity of GLS1, and the effect of preventing and / or treating aortic aneurysm is achieved.

The application relates to the biomedical application field of inorganic materials, and particularly relates to application of lanthanum carbonate in preparation of a medicine for treating hepatic encephalopathy. The application relates to application of lanthanum carbonate in preparation of a medicine for treating hepatic encephalopathy, wherein the medicine comprises lanthanum carbonate and pharmaceutically acceptable adjuvants, and the lanthanum carbonate comprises any one or more of lanthanum carbonate hydrate and basic lanthanum carbonate. The application is based on the fact that glutamine enzyme can reduce blood ammonia, and the hepatic encephalopathy is reversed by reducing blood ammonia and systemic inflammation, the liver function is recovered by regulating inflammation, thereby helping to cure the hepatic encephalopathy, and good treatment effect is shown, so that a new candidate medicine for clinically treating the hepatic encephalopathy is provided.

The invention discloses a method for deamidating and modifying peanut protein by using protein glutaminase, which comprises the following specific steps of: adding acetic acid / boric acid / NaOH buffer solution into peanut protein serving as a raw material while stirring to form protein dispersion liquid with certain substrate concentration; adding food-grade protein glutaminase into the peanut protein dispersion liquid for modification and termination; and carrying out vacuum freeze drying on the modified peanut protein dispersion liquid to obtain the deamidated modified peanut protein. Compared with unmodified peanut protein, the modified peanut protein obtained by the method disclosed by the invention has the advantages that the deamidation degree is obviously improved, the hydrolysis degree is not changed, and the functional properties such as solubility and foamability are all improved. The method for deamidating and modifying the peanut protein is simple in process and high in safety, can be used for large-scale industrial production and application, does not generate side reactions such as hydrolysis and crosslinking, and is beneficial to expanding the application scene of the peanut protein.

The invention relates to the technical field of pharmaceutical preparations, in particular to mRNA (messenger ribonucleic acid) lipid nanoparticles and application thereof in treatment of triple-negative breast cancer. The invention constructs an mRNA lipid nanoparticle, breaks through the dilemma of single drug curative effect of a glucose transporter (GLUT) inhibitor and a glutaminase (GLS) inhibitor for triple negative breast cancer, and realizes double-track treatment of mRNA metabolism reprogramming and small molecule energy deprivation for the first time. The mRNA lipid nanoparticles enhance the sensitivity of triple negative breast cancer to small molecule energy deprivation treatment, so that the clinical transformation feasibility of BAY-876 and CB-839 is improved to a new dimension. The delivery efficiency of the mRNA lipid nanoparticles is high, the biological safety is good, meanwhile, the production process of the nanoparticles is simpler and more standard compared with plasmids and viruses, and the drug production cost is lower.

The invention relates to a Chryseobacterium-derived protein glutaminase PG3, a coding gene and an application thereof, and belongs to the technical field of biological genetic engineering. The amino acid sequence of the protein glutaminase PG3 is as shown in SEQ ID No. 1, and the cDNA sequence of the coding gene of the protein glutaminase PG3 is as shown in SEQ ID No. 2. A large amount of protein glutaminase PG3 from Chryseobacterium is prepared through an Escherichia coli expression system, and the protein glutaminase is used for carrying out enzymatic deamidation modification on the spotted silver carp myofibrillar protein PG3, so that the solubility of the spotted silver carp myofibrillar protein under a salt-free system condition is remarkably improved. The invention provides an important tool enzyme for protein deamidation modification, and lays a theoretical foundation for development of low-salt fish protein processed products.

This invention belongs to the fields of genetic engineering and enzyme engineering technology, and discloses a glutaminase mutant, immobilized glutaminase, and their applications. The glutaminase mutant is based on the amino acid sequence shown in SEQ ID NO.1, with amino acid mutations at the following sites: E113K, R136M, and H223V, and its amino acid sequence is shown in SEQ ID NO.3. Immobilized glutaminase prepared using the glutaminase mutant exhibits 5-10 times increased enzyme activity compared to the wild type. The substrate concentration in the synthesis of L-theanine catalyzed by the immobilized glutaminase reaches 80-150 g / L, with a conversion rate greater than 99%. It can be recovered through simple filtration and reused more than 5 times, with the conversion rate remaining essentially the same during repeated use, demonstrating high potential for industrial application.