1305 results about "Glutamine" patented technology

The present disclosure provides certain piperidinylpyridinylcarbonitrile derivatives, and pharmaceutically acceptable salts thereof, that are inhibitors of Glutaminyl-peptide cyclotransferase (QPCT) and glutaminyl-peptide cyclotransferase-like protein (QPCTL), and are therefore useful for the treatment of diseases treatable by inhibition of QPCT / L. Also provided are pharmaceutical compositions containing the same, and processes for preparing said compounds.

The invention belongs to the technical field of biological medicines, and particularly discloses an epidermal growth factor-linker polypeptide-collagen, and the linker polypeptide has an amino acid sequence as shown in SEQ ID No.1. The linker polypeptide capable of connecting the EGF and the collagen is designed and synthesized, the N end of the linker polypeptide simulates an EGF receptor structure and can be combined with the EGF, and the linker polypeptide is connected with the EGF through non-covalent Van der Waals force, so that the structure of the EGF cannot be damaged; the C terminal of the linker polypeptide is rich in lysine residues, and can be covalently crosslinked to collagen through glutamine transaminase to form EGF-linker polypeptide-collagen. The protein solution taking EGF-linker polypeptide-collagen as active ingredients is low in cytotoxicity and high in biological safety, and meanwhile, the action time of the epidermal growth factor can be remarkably prolonged. In addition, a stable repairing microenvironment can be formed on the surface of the endometrium, and the endometrium injury repairing effect is remarkably improved.

The invention relates to the field of microorganisms, and discloses an Aspergillus oryzae strain and application thereof.The Aspergillus oryzae can produce protease, aminopeptidase, glutaminase, cellulase, amylase and pectinase at high yield, and when the Aspergillus oryzae is applied to soy sauce brewing, the utilization rate of raw materials can be increased, the content of amino acid in soy sauce can be increased, and the flavor of the soy sauce can be increased.

The invention discloses a method for preparing an animal adipose tissue simulant by using soybean protein and application of the animal adipose tissue simulant, and belongs to the technical field of deep processing of vegetable protein. Soybean protein is used as a raw material, the soybean protein and polysaccharide are compounded and heated to form thermal induction gel, then microgel particles are obtained through mechanical shearing and crushing, and recombinant soybean protein emulsion gel, namely the animal adipose tissue simulant, is prepared through vegetable oil emulsification and glutamine transaminase covalent cross-linking. The fat-reducing sausage is used as a substitute of pig back fat and is applied to development of fat-reducing sausages. The animal adipose tissue simulant prepared by the invention has texture and melting characteristics similar to those of animal pig back fat. The invention provides the preparation method of the plant-based fat simulant, which meets the requirements of environmental protection and health and sustainable production, not only meets the requirements of texture and melting characteristics of solid fat, but also provides technical support for high-value application of soybean protein in the field of plant meat foods.

The invention provides multifunctional hydrogel, drug-loaded hydrogel as well as a preparation method and application of the multifunctional hydrogel and the drug-loaded hydrogel, and belongs to the technical field of biological medicines. According to the multifunctional hydrogel provided by the invention, the gelatin, the transglutaminase and the sulfhydrylated hyaluronic acid are used as preparation raw materials, so that the problem of limited performance of a hydrogel product in the prior art is solved. According to the hydrogel product prepared by the invention, cell adhesion can be provided through a transglutaminase cross-linked gelatin network, meanwhile, an ROS removal effect is provided through a dynamic disulfide bond cross-linked hyaluronic acid network, and degradation of the hydrogel can be regulated and controlled through combination of the two networks; according to the drug-loaded hydrogel provided by the invention, the exosome derived from neural stem cells is additionally encapsulated in the hydrogel, the exosome and the hydrogel jointly achieve the effects of enhancing inhibition of glial scars and resisting inflammation, and the material provided by the invention can promote repair and regeneration of neurons and myelin sheaths, so that the drug-loaded hydrogel can be used for preparing cerebral hemorrhage treatment drugs and can be used for preparing drugs for treating cerebral hemorrhage. And an effective means is provided for the treatment of related diseases.

The invention relates to the technical field of dye synthesis, and particularly discloses a genetically engineered bacterium for synthesizing N-acetyl blue as well as a construction method and application of the genetically engineered bacterium. The supply capacity of precursor substances glutamic acid and glutamine of the genetically engineered bacterium is high, the fermentation process is simple, the production intensity of the precursor substances glutamine and N-acetylglutamine is improved by cutting off a consumption path, relieving negative feedback inhibition and enhancing the expression level of key genes through the genetically engineered bacterium, and finally the yield of N-acetylblue reaches 41.2 g / L.

The invention relates to the field of polypeptide compositions, in particular to a polypeptide metal chelate and application thereof in the field of cosmetics, and the polypeptide metal chelate is formed by chelating a polypeptide compound and a metal ion compound. The structure of the polypeptide compound is [gamma-Glu] n-AA, n is greater than or equal to 1, and AA is selected from glycine, alanine, valine, leucine, isoleucine, methionine (methionine), proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, asparaginic acid, glutamic acid, lysine, arginine or histidine; the polypeptide chelated zinc prepared by the invention has remarkable oil control and anti-inflammatory effects, and can be compounded with other raw materials to form cosmetics with oil control and acne removal effects.

The invention relates to a composition for improving mildness and stability of a sunscreen product and application of the composition. The composition comprises a sphingomonas fermentation product extract, bis (lauramide glutamine) lysine sodium and a wild soybean seed extract. The invention creatively discovers that the three components of the sphingomonas fermentation product extract, the bis (lauramide glutamine) lysine sodium and the wild soybean seed extract are compounded for use, have a synergistic effect and can play a role under a low addition amount, so that the stability of the sunscreen product is improved, the irritation is reduced, the use experience is improved, and the sunscreen effect is improved. And moreover, the cost is effectively and reasonably reduced, and great market potential and economic value prospects are achieved.

The invention relates to preparation of high-stability mascarpone cheese and application of the mascarpone cheese in baking, and belongs to the technical field of cheese preparation. The glutamine transaminase is combined with a citric acid-sodium citrate system, so that the excessive denaturation of protein is reduced, and the texture and flavor of the cheese are improved. Trehalose and xanthan gum are added for locking water and resisting freezing, and an antioxidant is combined for use, so that the freeze-thaw stability and oxidation resistance of the cheese are improved, the cheese is protected from texture change and oxidative damage in the freezing and unfreezing processes, and excellent texture and flavor can still be kept after multiple times of circulation. Arabic gum is modified through octenyl succinic anhydride, amphipathy is obtained, whey separation is prevented, whey loss is reduced, and the cheese taste is improved.

The invention discloses a milk-flavor jelly-shaped intelligent response type suckling pig creep compound feed and a preparation method, relates to the technical field of animal feeds, and aims to solve the problems that a traditional feed is poor in palatability, nutrition release and physiological needs are mismatched, thermosensitive components are damaged by a high-temperature process and the like. And accurate release of nutrients is realized. The feed comprises an energy raw material, a protein raw material, intelligent response components (pH-sensitive sodium alginate microsphere loaded sodium butyrate / glutamine, temperature-sensitive xanthan gum-locust bean gum compound gel coated antibacterial peptide, and enzyme-sensitive lysine-lysine peptide bond cross-linked layer embedded glucose compound enzyme), a flavor system (vanillin microcapsules) and a konjac gum jelly matrix. A pH-temperature-enzyme triple response mechanism is adopted to adapt to the gastric acid gradient, body temperature fluctuation and pancreatin activity of suckling pigs; milk flavor slow release and nutrition release are in space-time synergy, and the ingestion frequency is increased by 40%; the konjac glucomannan matrix reduces dust, and the gel strength is greater than or equal to 750g / cm.

The invention provides universal functional formula milk powder for cats and dogs and a preparation method thereof, and relates to the field of pet formula food. The formula milk powder consists of goat milk powder, colostrum powder, whey protein powder, lactoferrin powder, yolk powder, immune globulin powder, compound grease, compound minerals, compound vitamins, choline, taurine, compound prebiotics, compound probiotics, docosahexaenoic acid, arachidonic acid, casein phosphopeptides, L-glutamine and beta-galactosidase. And the goat milk powder, colostrum powder, whey protein powder, lactoferrin powder, yolk powder and immune globulin powder are subjected to low-temperature sterilization treatment by adopting an induced electric field or high-pressure microjet. The cat and dog formula milk powder overcomes the defects in the prior art, through compounding of basic nutritional ingredients and functional ingredients, a novel low-temperature sterilization technology is adopted for sterilization treatment, on the premise that the functionality of the formula milk powder is guaranteed, the nutritional value of the formula milk powder is reserved to a greater extent, and healthy growth and development of cats and dogs are promoted.

Certain C. glutamicum strains overexpress genes coding for enzymes having the function of aspartate-semialdehyde dehydrogenase, aspartate aminotransferase, dihydrodipicolinate synthase, dihydrodipicolinate reductase, diaminopimelate decarboxylase, aspartatokinase and diaminopimelate dehydrogenase. The C. glutamicum strains also express NAD(P)(+) transhydrogenase subunit alpha PntA and NAD(P)(+) transhydrogenase subunit beta PntB of Corynebacterium urealyticum. A method is developed for the fermentative production of L-lysine using such C. glutamicum strains.

The present invention provides a phycocyanin-collagen composite hydrogel and its preparation method and application. The present invention utilizes transglutaminase to catalyze the combination of phycocyanin and collagen to form a new, more stable collagen; transglutaminase acts between protein molecules, utilizes lysine and glutamic acid in phycocyanin and collagen to transfer acyl groups, and cross-links to form new chemical bonds, thereby enhancing the binding strength of phycocyanin and collagen; the hydrogel prepared by the present invention can be used to prepare medical materials and combined with skin injury sites to solve the problem that traditional dressings are easy to adhere to wounds and easily penetrated by tissue fluid and become infected. In addition to ensuring basic air permeability, it reduces the adhesion of the dressing, increases moisture retention and antioxidant properties, and avoids secondary damage when replacing a new dressing. The hydrogel prepared by the present invention has a certain antioxidant capacity and can be used to prepare products with antioxidant effects.

The invention relates to the technical field of biomedicine, and discloses a human metapneumovirus culture method which comprises the following steps: a culture medium is prepared and put into a culture bottle, and the culture medium comprises a DMEM culture medium, glucose, sodium bicarbonate, an HEPES buffer solution, chondroitin sulfate and hyaluronic acid; host cells are selected; preparing a culture solution, wherein the culture solution comprises L-glutamine, bovine serum albumin, antibiotics and N-acetylcysteine; and inoculating the human metapneumovirus into the culture medium for adsorption and infection. The chondroitin sulfate and the hyaluronic acid are added into the culture medium, the chondroitin sulfate and the hyaluronic acid can be combined with glycosaminoglycans on the surfaces of the host cells to form a compound, interaction sites of viruses and the host cells are increased, then virus receptor expression on the surfaces of the host cells is enhanced, the cell membrane environment is optimized, and therefore the anti-tumor effect is achieved. Therefore, the attachment and entry efficiency of the hMPV is improved, and the rapid proliferation of the virus is obviously promoted.

The application relates to an engineering bacterium for high yield of observation blue and a construction method and application thereof, and belongs to the technical field of biological synthesis of natural dyes. The engineering bacterium for high yield of observation blue expresses icd, bpsA, glnA Y405F and gdhA; the engineering bacterium knocks out acnR, yggB, glsK, aceA and ldh. By knocking out the yggB and aceA genes, performing site-directed mutation (Y405F) on the glnA gene, replacing the glsK gene with the glnA Y405F gene, replacing the acnR gene with the icd gene, replacing the ldh gene with the gdhA gene, and integrating the bpsA gene, the application can block the formation of by-products such as lactate and succinic acid in the observation blue synthesis process, improve the flow direction of the citric acid->isocitric acid->alpha-ketoglutaric acid->glutamic acid->glutamine path, and then improve the intracellular glutamine concentration, so that the yield of observation blue is improved.

The invention discloses a pharmaceutical composition for promoting aTreg cell differentiation and application thereof, and relates to the field of biological medicine, and the pharmaceutical composition comprises zinc salt, a basic cell culture medium, fetal calf serum, antibiotic, L-glutamine and a pH buffer agent. According to the application, the basic cell culture medium is used for providing basic nutrition required by cell growth for lymphocytes, the fetal calf serum is used for providing growth factors, hormones, adhesion proteins and nutrient substances required by cell growth for the lymphocytes, and the antibiotics are used for preventing bacterial infection; l-glutamine provides key amino acid for cell energy metabolism and participates in synthesis of protein and nucleic acid, zinc salt provides zinc ions, and under the comprehensive action, the proportion of Treg cells and aTreg cells differentiated from lymphocytes in peripheral blood mononuclear cells is increased.

A boron carrying agent, a preparation method therefor, and a pharmaceutical formulation. The boron carrying agent contains compound 1, N-4-carboxyphenylboronic acid amide-threonine-phenylalanine-phenylalanine-tyrosine-glycine-glycine-serine-arginine-glycine-lysine-arginine-aspartic acid-aspartic acid-phenylalanine-lysine-threonine-glutamic acid-glutamic acid-tyrosine-cysteine, having a molecular formula of C114H158BN30O35S1 and a molecular weight of 2552.4, and further contains compound 2, N-4-carboxyphenylboronic acid amide-arginine-lysine-lysine-lysine-arginine-arginine-glutamine-arginine-arginine-arginine, and / or compound 3, N-4-carboxyphenylboronic acid amide-methionine-alanine-serine-methionine-threonine-glycine-glycine-glutamine-glutamine-methionine-glycine. Compounds 1-3 can serve as a targeted medicament for boron neutron capture therapy used for treating a cerebral glioma and a head and neck tumor.

The present application relates to the technical field of biocatalysis and biosynthesis, and specifically discloses a natural blue pigment and a biosynthesis method therefor. The present application uses metabolically engineered bacteria to express indigoidine synthetase and phosphopantetheinyl transferase, to catalyze glutamine and N-acetylglutamine to biosynthesize a natural blue pigment N-acetylindigoidine, and deduces its molecular structure by means of mass spectrometry, nuclear magnetic resonance and other methods. The present application achieves catalytic synthesis of N-acetylindigoidine from glutamine and N-acetylglutamine in Escherichia coli, Corynebacterium glutamicum, Saccharomyces cerevisiae and Streptomyces. Compared with indigoidine, N-acetylindigoidine has a maximum absorption wavelength of 584 nm, possesses better color brightness, and has more stable coloration that is not easily faded, with a very broad application range and industrial production application prospects.

The invention provides construction and application of a hyaluronic acid recombinant bacterium, and belongs to the fields of biochemical engineering, synthetic biology, genetic engineering and metabolic engineering, the recombinant corynebacterium glutamicum contains a hyaluronic acid synthase gene, a UDP-glucose dehydrogenase gene and a glutamide-6-phosphate fructose transaminase gene; the hyaluronic acid synthase gene, the UDP-glucose dehydrogenase gene and the glutamine-6-phosphate fructose transaminase gene are respectively connected with a sequence RBS1, a sequence RBS2 and a sequence RBS3; the recombinant bacterium provided by the invention also contains a dCas9 protein gene dCas9 and any one of genes sgRNA1, sgRNA2, sgRNA3, sgRNA4, sgRNA5 and sgRNA6, and the recombinant bacterium provided by the invention is high in hyaluronic acid yield and low in production cost.

The invention relates to the field of cell biology, and particularly discloses a method for preparing mesoderm progenitor cells from human pluripotent stem cells and an induced differentiation culture medium of the mesoderm progenitor cells. The method comprises the following steps: inoculating human pluripotent stem cells in a single cell state into a culture dish covered with matrigel; and inducing the human pluripotent stem cells to be differentiated into the mesoderm progenitor cells within 1-3 days by using the mesoderm progenitor cell induced differentiation culture medium. Wherein the mesoderm progenitor cell induced differentiation culture medium is composed of a basic culture medium and an additive, and the additive contains a B-27 additive, non-essential amino acid, glutamine, ascorbic acid, polyvinyl alcohol, a GSK-3 inhibitor and a CDK8 inhibitor. According to the method, the human pluripotent stem cells are subjected to induced differentiation by using the mesoderm progenitor cell induced differentiation culture medium with specific composition, the method does not depend on cloning of the pluripotent stem cells, a large number of high-uniformity mesoderm progenitor cells can be obtained through induced differentiation within 1-3 days, the induction efficiency is high, and the stability is high.

The invention belongs to the technical field of biological medicines, and particularly discloses an insulin-like growth factor-1-linker polypeptide-collagen, and the linker polypeptide has an amino acid sequence as shown in SEQ ID No.1. The N end of the designed and synthesized linker polypeptide simulates an IGF-1 receptor structure and can be combined with IGF-1, the C end of the linker polypeptide is rich in lysine residues and can be covalently cross-linked to collagen through glutamine transaminase, the attachment time of the IGF-1 in endometrium is prolonged, and endometrium thickening and endometrium injury repair are effectively promoted. The protein solution for promoting endometrial injury repair provided by the invention can form a stable repair microenvironment on the surface of the endometrial, promote the number recovery of endometrial glands with intrauterine adhesion, reduce the fibrosis ratio and promote the thickening of thin endometrial, has the advantages of high histocompatibility, simplicity in preparation, obvious improvement effect and the like, and can be used for preparing a medicine for treating endometrial injury. The method has no potential toxic influence on cells and has a good clinical application prospect.

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 present application relates to the technical field of biocatalysis and biosynthesis, and specifically discloses a blue pigment and a biosynthesis method thereof. In the present application, an indigoidine synthetase and a 4′-phosphopantetheinyl transferase are expressed by a metabolically engineered strain to catalyze the biosynthesis of the blue pigment N-acetyl-indigoidine from glutamine and N-acetylglutamine, and a molecular structure of the blue pigment is inferred by mass spectrometry, nuclear magnetic resonance spectroscopy, etc. The present application achieves the catalytic synthesis of N-acetyl-indigoidine from glutamine and N-acetylglutamine in Escherichia coli (E. coli), Corynebacterium glutamicum (C. glutamicum), Saccharomyces cerevisiae (S. cerevisiae), and Streptomyces. Compared with indigoidine, N-acetyl-indigoidine has a maximum absorption wavelength of 584 nm, and a stable color having high brightness that is not easy to fade. Thus, the blue pigment shows an extensive application range and a promising industrial production prospect.

The invention discloses a composition for improving the stability of oleuropein in a solution as well as a preparation method and application of the composition. The composition comprises oleuropein and at least one stabilizer, and the stabilizer is selected from the group consisting of anisic acid, lactobionic acid, glycyrrhizic acid, 3, 3-thiodipropionic acid, N-acetyl-L-glutamine, propyl-cysteine and lauramidopropyl betaine; and the pH value of the aqueous solution of the composition is 4.0-8.0. The preparation method comprises the following steps: dissolving oleuropein in water, adding the stabilizer, and uniformly mixing. Through simple physical mixing, by utilizing the synergistic effect of the specific stabilizer and the oleuropein, the degradation and discoloration of the oleuropein in the storage process are remarkably inhibited. Experiments show that after the preferable composition is preserved for 30 days in an open manner, the retention rate of the oleuropein still reaches up to 80% or above, and is far superior to that of blank control and a traditional liposome wrapping method. The composition is simple and convenient in preparation process and low in cost, and provides reliable technical support for wide application of oleuropein in liquid products such as food, medicine and cosmetics.

The invention relates to the technical production field of metabolic engineering and genetic engineering, and particularly provides a genetically engineered bacterium for producing 2 '-deoxyuridine as well as a construction method and application of the genetically engineered bacterium. According to the strain, deoxyuridine kinase tdk is knocked out on an E.coli W3110 genome, and T7 RNA polymerase is integrated; an aspartate transaminase gene aspC, a glutamine synthetase gene glnA, a 5 '-deoxynucleotidase gene yfbR and a uridine monophosphate kinase gene pyrH are subjected to overexpression; the method comprises the following steps: introducing a ribonucleoside diphosphate reductase gene nrdBCA from Escherichia phage T4 in a heterologous series connection manner; the CTP synthase gene pyrG * of Corynebacterium glutamicum is introduced in a heterologous mode, and the CTP synthase gene pyrG * of Corynebacterium glutamicum is introduced in a heterologous mode. The safe, efficient and low-cost production of the 2 '-deoxyuridine is realized.

The invention discloses a composite sunscreen composition with excellent film-forming property and sunscreen stability as well as a preparation method and application thereof, and belongs to the technical field of daily chemicals. The composite sunscreen composition is prepared from inulin lauryl carbamate, bis (lauramide glutamine) lysine sodium, hydroxypropyl trimethyl ammonium chloride hyaluronic acid, an ammonium acryloyldimethyl taurate / VP copolymer, a sunscreen agent, basic grease, and cosmetically acceptable auxiliary materials and a solvent, the sunscreen emulsion prepared on the basis of the composition can quickly form a stable, light, thin and breathable sunscreen film on the surface of skin, solves the problems that a sunscreen agent in a traditional sunscreen product is non-uniform in agglomeration and dispersion, a formed film is rigid and airtight, the sunscreen effect is easy to lose due to sweating / friction, the skin feeling is poor and the like, and has the advantages of high sunscreen stability, excellent water resistance and good skin feeling; the method can be widely applied to preparation of skin care products with a sunscreen effect.

The invention discloses a genetically engineered bacterium for producing pseudouridine and a construction method of the genetically engineered bacterium, escherichia coli W3110 is used as a starting strain, the supply of precursor substances including aspartic acid, carbamyl phosphoric acid, glutamine and 5 '-phosphoribosyl pyrophosphate prpp is enhanced, pyrimidine nucleoside synthesis operon from bacillus subtilis is introduced, and the pseudouridine is produced. The invention discloses a pseudouridine-5 '-phosphosidase gene psuG and a preparation method thereof, and relates to the field of microorganisms, the field of genetic engineering and the field of fermentation engineering. The pseudouridine-5'-phosphosidase gene psuG is expressed by using high-copy plasmids, and the application of the pseudouridine-5 '-phosphosidase gene psuG to preparation of the pseudouridine-5'-phosphosidase gene psuG is provided. The strain is fermented in a 50L fermentation tank for 60h, the yield of pseudouridine reaches 50.8 g / L, the conversion rate is 18%, which is the highest value reported at present, and the strain has high industrial production value.

The invention discloses a preparation method and processing equipment of herbal composite granules, and relates to the technical field of composite granules. Comprising the following components in parts by weight: 15-20 parts of soybean phospholipid, 10-15 parts of glutamine, 10-15 parts of L-arginine, 5-10 parts of a ginseng extract, 5-10 parts of phytosterol, 5-10 parts of xylooligosaccharide, 5-10 parts of inositol, 5-10 parts of a hawthorn extract, 5-10 parts of a blueberry extract, 5-10 parts of an acerola cherry extract, 0-5 parts of yeast beta glucan, 0-5 parts of a sea-buckthorn extract, 0-5 parts of a tartary buckwheat extract, 0-5 parts of haematococcus pluvialis and the like. The composition is innovative and breakthrough in successful application in the aspects of heart and cerebral vessels and anti-aging, and can regulate intestines, protect liver, reduce blood pressure and regulate blood fat; thrombus is melted, the vascular endothelial function is improved, and arteriosclerosis is prevented; meanwhile, the effects of resisting oxidation, resisting inflammation, resisting aging and enhancing immunity can also be achieved.

The invention discloses starch-collagen composite hydrogel as well as a preparation method and application thereof. Collagen is catalyzed by microbial transglutaminase to form a covalent cross-linked network, and meanwhile, hydroxypropyl starch is introduced to construct a physical interpenetrating network through molecular chain penetration and hydrogen-bond interaction; and chondroitin sulfate is further integrated to strengthen the network structure and biological activity through electrostatic interaction. The method is mild in condition and does not need a toxic chemical cross-linking agent, the obtained composite hydrogel has an interpenetrating double-network structure and has excellent mechanical properties, enzymatic degradation resistance and cell affinity, the compression modulus of the composite hydrogel is remarkably improved, the composite hydrogel can keep structural stability for a long time in a collagenase environment, cell adhesion and proliferation can be effectively promoted, and the composite hydrogel has a good application prospect. The hydrogel can be widely applied to tissue engineering scaffolds, wound dressings, drug sustained-release carriers and cartilage repair materials.

The invention provides a cellobiose epimerase mutant E250Q, an engineering bacterium and application of the cellobiose epimerase mutant E250Q, and belongs to the technical field of genetic engineering. According to the invention, glutamic acid at the 250th site of an amino acid sequence of wild cellobiose epimerase is mutated into glutamine, so that the cellobiose epimerase mutant E250Q is obtained. The amino acid sequence of the cellobiose epimerase mutant disclosed by the invention is shown as any one of SEQ ID NO.1-6. The invention further discloses a preparation method of the cellobiose epimerase mutant. According to the method, recombinant bacteria or cellobiose epimerase mutant E250Q is used as a catalyst, lactose is used as a substrate, the conversion rate of converting lactose to lactulose reaches 67.1%, the yield of brepinose is only 4.0-5.7% and is lower than the by-product proportion permitted by Chinese Pharmacopoeia, and the method has extremely high application value in industrial production of lactulose.