62 results about "Glucosyltransferase" patented technology

The present application belongs to the technical field of oral care, and particularly relates to an oral care composition and a preparation method thereof. The oral care composition comprises, by mass percentage, chitosan oligosaccharide 0.1-0.3%, sea hao polysaccharide 0.08-0.14%, forskolin 0.07-0.12%, corn sprout extract 0.05-0.09%, thickening agent 1-3%, humectant 40-50%, and the balance being water. The oral care composition of the present application can effectively inhibit the activity of glucosyltransferase, inhibit the production of dextran, interfere with the formation process of dental plaque, and reduce the adhesion sites of pathogenic bacteria in the oral cavity. In addition, the composition of the present application can promote the proliferation and repair of oral mucosa epithelial cells, and help repair oral mucosa damage. Furthermore, the use of each component in the composition of the present application can balance the oral microbial flora, while achieving the effect of inhibiting pathogenic bacteria and improving the oral environment.

The invention discloses high-purity resistant dextrin and a preparation method thereof, and the preparation method comprises the following steps: (1) adding 4, 3-alpha-glucosyltransferase into a maltodextrin aqueous solution or a starch solution treated by starch debranching enzyme to react, and after the reaction is finished, deactivating the enzyme; (2) adding alpha-amylase into a reactant in the step (1) to react, and deactivating the enzyme after the reaction is finished; (3) adding alpha-glucosidase into the reactant in the step (2) for reaction, and deactivating the enzyme after the reaction is finished; (4) adding saccharifying enzyme into the reactant in the step (3) to react, and deactivating the enzyme after the reaction is finished; and (5) adding yeast powder into the reactant in the step (4) for fermentation, filtering by a filter membrane after fermentation, collecting membrane filtrate, and drying to obtain the high-purity resistant dextrin. The preparation process is simple and efficient, the product purity is high, the proportion of alpha-1, 3 glucosidic bonds in the prepared resistant dextrin is 40% or above, and the purity of the resistant dextrin is 80-90%.

Disclosed herein are methods of producing a food product or food precursor. These methods can comprise, for example, (a) providing milk, (b) adding sucrose to the milk to form sweetened milk, (c) contacting the sweetened milk with at least one glucosyltransferase to form insoluble alpha-glucan in the milk, (d) acidifying the milk product to a pH below about 5.0, and (e) inactivating the glucosyltransferase by subjecting the acidified milk product to a temperature of about 70-110 °C. Such methodology can produce an acidified milk product having a stable sucrose level and typically also a stable level of texture. Such methodology can optionally use other types of food products / precursors instead of milk, as appropriate. One or more glucosyltransferases used in the methodology can be selected from (i) a glucosyltransferase that synthesizes alpha-1,6-glucan, and / or (ii) a glucosyltransferase that synthesizes alpha-1,3-glucan. Food products / precursors produced by this methodology are also disclosed.

A glucosyltransferase catalyzing RA to produce RM and a use thereof are provided. The glucosyltransferases derived from Cornus florida and Juglans regia L. are screened and obtained. It was found that the glucosyltransferase derived from the Cornus florida exhibited a relatively high enzymatic activity in catalyzing the RA to produce the RD, while the glucosyltransferase derived from the Juglans regia L. exhibited a relatively high enzymatic activity in catalyzing the RD to produce the RM. When these two enzymes were used together in catalyzing the RA to produce the RM, a relatively high conversion rate was achieved. The use of the glucosyltransferases derived from the Cornus florida and the Juglans regia L. for preparing the RM of SGs, has not been reported yet. The glucosyltransferase provides an excellent candidate protein resource and its corresponding gene sequence for the enzymatic conversion process of the SGs.

The application relates to the field of biological medicine, and discloses a glucosyltransferase mutant, a coding gene of the glucosyltransferase mutant, a recombination carrier, a recombination strain, an enzyme preparation, and application of the glucosyltransferase mutant. The glucosyltransferase mutant is a point mutation at the R position of the amino acid sequence shown in SEQ ID NO:1, and 4-8 histidines are added at the N end. A method for preparing gastrodin comprises the following steps: contacting the glucosyltransferase mutant with p-hydroxybenzyl alcohol and uridine diphosphate glucose. The glucosyltransferase mutant provided by the application has higher specificity for the substrate p-hydroxybenzyl alcohol, thereby obviously improving the conversion rate of the conversion of p-hydroxybenzyl alcohol into gastrodin, and having a good industrial application prospect.

The invention provides immobilized cyclodextrin glucosyltransferase as well as a preparation method and application thereof and a preparation method of ascorbic acid glucoside, and belongs to the technical field of enzymes, the technical field of biological catalysis and the technical field of preparation of chemical raw material medicines. The preparation method of the immobilized cyclodextrin glucosyltransferase comprises the following steps: activating a carrier; mixing the activated carrier with a solution containing cyclodextrin glucosyltransferase, stirring, carrying out solid-liquid separation, and washing to obtain an immobilized enzyme; and mixing the obtained immobilized enzyme with a polyethylene glycol-polyethyleneimine copolymer solution, stirring, carrying out solid-liquid separation, and washing to obtain the immobilized cyclodextrin glucosyltransferase. The immobilized cyclodextrin glucosyltransferase prepared by the preparation method is high in catalytic activity and good in use stability, and when the immobilized cyclodextrin glucosyltransferase is applied to catalytic synthesis of ascorbic acid glucoside, high-content and high-yield ascorbic acid glucoside can be obtained.

The present disclosure relates, in part, to addition of glucosyl- or glucano-transferase type enzymes for producing and / or modifying alpha-glucan type structures in dough such as bread dough. Such enzymes encompass, for example, (i) dextrin dextranases, (ii) glucosyltransferases, and (iii) glucosyl-, maltosyl-, maltotetrasyl-, or glucano-transferases, where these enzymes can transfer glucose to / from starch and starch hydrolysate substrates (e.g., dextrin, amylodextrin, and / or maltodextrin) for production and / or modification of alpha-glucan type polymers in bread dough. Further disclosed are methods of preparing a baked food product by baking a farinaceous dough, comprising incorporating into the dough one or more of the foregoing enzymes – e.g., a glucosyl- or glucano-transferase type enzyme – wherein the enzyme can transfer a glucose-based moiety from a polysaccharide or oligosaccharide substrate to the non-reducing end of an oligosaccharide acceptor, thereby improving bread volume and / or dough stability. Further disclosed are modified alpha-glucans for use as food ingredients in general.

The invention discloses an application of UDP (User Datagram Protocol) glucosyltransferase in microbial production of rosavin and rosavin. The UDP glucosyltransferase is used for catalyzing cinnamyl alcohol and UDP-glucose to generate rosai and is coded by an OsUGT13 gene of oryza sativa, and the catalytic efficiency of the UDP glucosyltransferase is 3.6 times that of UDP glucosyltransferase coded by a Bs-YjiC gene from bacillus subtilis. The method can be used for large-scale industrial production of rosavin and the derivative rosavin thereof, and has application value.

The invention discloses a preparation method of glucosyl puerarin, which belongs to the technical field of pharmaceutical chemicals, and comprises the following steps: S1, adding sugar for reaction, mixing puerarin with pure water, adjusting the pH value to 4.5-5.5, adding beta-cyclodextrin, heating to 45-55 DEG C, adding cyclodextrin glucosyltransferase for reaction for 16-22 hours, then adjusting the pH value to 0.1-0.8, adding activated carbon, filtering filtrate and staying overnight at low temperature; s2, desugaring reaction: adjusting the pH value of the filtrate to 3.8-4.5, heating to 55-65 DEG C, adding saccharifying enzyme and glucose oxidase to react for 25-40 minutes, adjusting the pH value to 0.5-1.2, and filtering; s3, column purification: enabling a reaction solution to pass through a mixed column containing sulfonated modified XAD-16 and amino modified HPD-720 resin, and performing graded elution to collect an ethanol eluent; s4, concentrating and drying to obtain a product. The problems that the water solubility of puerarin is poor, the purity of glucosyl puerarin is low, and impurities are difficult to remove can be solved.

The present invention relates to a UDP-glucosyltransferase variant, a fusion enzyme of UDP-glucosyltransferase variants, and a use thereof for producing steviol glycoside. The UDP-glucosyltransferase variant and the fusion enzyme of UDP-glucosyltransferase variants according to the present invention have improved enzymatic activity. In addition, the fusion enzyme of UDP-glucosyltransferase variants has further improved enzymatic activity compared to when each variant is used individually. Accordingly, the UDP-glucosyltransferase variant and the UDP-glucosyltransferase variant fusion enzyme according to the present invention can be widely applied in the field of steviol glycoside synthesis, and have excellent commercial value and significance in that production efficiency can be increased and production costs can be reduced.

The invention discloses a glycosyl transferase mutant for synthesizing rebaudioside M as well as a product and application thereof, and belongs to the technical field of gene engineering. The technical problem to be solved is that the existing glycosyl transferase and sucrose synthase are low in enzyme activity and insufficient in enzyme activity stability, so that the synthesis efficiency of rebaudioside M (RebM) is not high, and the industrial application of preparing RebM by an enzyme method is limited. According to the key points of the technical scheme, the glycosyl transferase mutant is provided, the mutant is obtained by mutating UDP-glycosyl transferase UGT76G1, and the amino acid sequence of the UDP-glycosyl transferase UGT76G is as shown in SEQ ID NO. 1; the mutation comprises mutation on the 83rd site of SEQ ID NO.1, and the amino acid sequence of the glycosyl transferase mutant is shown as SEQ ID NO.5. The invention further discloses a preparation method of the glycosyl transferase mutant.

The invention discloses an immobilized recombinant whole-cell catalyst and a method for preparing gamma-cyclodextrin from the immobilized recombinant whole-cell catalyst. The recombinant whole-cell catalyst is prepared by immobilizing recombinant genetically engineered bacterium whole-cells for expressing a high-selectivity gamma-cyclodextrin glucosyltransferase mutant (the amino acid sequence is as shown in SEQ ID NO: 2) in a calcium alginate carrier matrix through an embedding method. The invention also provides a preparation method of the catalyst and application of the catalyst in preparation of gamma-cyclodextrin by catalyzing starch conversion in multi-batch reaction. The immobilized whole-cell catalyst is simple in preparation process and low in cost, has the high enzyme activity utilization rate of free whole cells and the excellent operation stability of immobilized enzyme, the enzyme activity retention rate is still 85% or above after the immobilized whole-cell catalyst is repeatedly used for 8 times at the temperature of 60 DEG C, and the proportion of a gamma-cyclodextrin product can be kept not lower than 96%.

The invention discloses an acid-resistant cyclodextrin glycosyl transferase (CGTS) mutant and an application of the acid-resistant cyclodextrin glycosyl transferase CGTase mutant. The acid-resistant cyclodextrin glycosyl transferase CGTase mutant has the advantages that the acid-resistant cyclodextrin glycosyl transferase CGTase mutant can be used as an acid-resistant mutant; the CGTase is subjected to multi-site directed mutation based on an artificially designed wild type sequence (the amino acid sequence is as shown in SEQ ID NO: 2), and an acid-resistant mutant (the amino acid sequence is as shown in SEQ ID NO: 16) with the optimal reaction pH of 5.0 is obtained. The mutant can maintain more than 80% of catalytic activity in a pH range of 4.0-5.5, and can be stabilized for 10 hours under a strong acid condition (pH is 4.0). Compared with a wild type, the mutant has a higher conversion rate, a shorter reaction period and better substrate stability in the process of synthesizing 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G), the industrial production efficiency of the AA-2G can be remarkably improved, and the mutant has an important application value.

Disclosed herein are glucosyltransferases with modified amino acid sequences. Such engineered enzymes have modified alpha-1,3-branching activity. Further disclosed are reactions and methods in which engineered glucosyltransferases can be used to add one or more alpha-1,3 branches to a suitable acceptor such as glucan.

The application discloses a preparation method of rebaudioside D and rebaudioside M and application of a beta-1,2-glucosyltransferase in the method. The beta-1,2-glucosyltransferase has an amino acid sequence as shown in SEQ ID NO: 4, or has a mutant amino acid sequence with at least 99% sequence identity compared with the amino acid sequence as shown in SEQ ID NO: 4. The application improves the yield of rebaudioside D, an intermediate product in the catalysis of rebaudioside A to generate rebaudioside M by the beta-1,2-glucosyltransferase, and accordingly, the yield of the final product rebaudioside M is improved.

The invention discloses an organic selenium composition, a preparation method and application of the organic selenium composition in preparation of antitumor drugs, and belongs to the technical field of enzyme-containing preparations, the preparation method comprises five steps of carrier activation, immobilization of double enzymes, immobilization of a third enzyme, in-situ synthesis and separation and purification; aminated mesoporous silica nanoparticles are used as a carrier, selenocysteine beta-lyase, UDP-glucosyltransferase and glucose dehydrogenase are immobilized through glutaraldehyde crosslinking, an immobilized three-enzyme system is constructed, and organic selenium is synthesized in situ by catalyzing substrates such as jerusalem artichoke polysaccharide and selenocysteine in a nitrogen atmosphere. And separating and purifying to obtain the organic selenium composition. The problems of easy enzyme inactivation, large coenzyme dosage, poor product stability and the like in the prior art are solved, and the prepared organic selenium composition is high in selenium content, concentrated in molecular weight, excellent in bioavailability and low in toxicity, can be used as an active component for preparing antitumor drugs, and has a good application prospect.

The application provides a glucosyltransferase and a derivative thereof obtained by a directed evolution method, application and preparation method, and belongs to the technical field of enzyme engineering. The glucosyltransferase provided by the application is obtained by a directed evolution method, the amino acid sequence of the glucosyltransferase is a sequence shown in SEQ ID NO. 4, and the DNA sequence of the glucosyltransferase comprises a sequence shown in SEQ ID NO. 3. The glucosyltransferase has strong catalytic ability, can significantly and efficiently catalyze flavone to generate flavone-7-O-glycoside, and can significantly reduce the generation of precipitates in plant extracts.

Disclosed herein are methods of producing a food product or food precursor. These methods can comprise, for example, (a) providing milk, (b) adding sucrose to the milk to form sweetened milk, (c) contacting the sweetened milk with at least one glucosyltransferase to form insoluble alpha-glucan in the milk, (d) acidifying the milk product to a pH below about 5.0, and (e) inactivating the glucosyltransferase by subjecting the acidified milk product to a temperature of about 70-110 °C. Such methodology can produce an acidified milk product having a stable sucrose level and typically also a stable level of texture. Such methodology can optionally use other types of food products / precursors instead of milk, as appropriate. One or more glucosyltransferases used in the methodology can be selected from (i) a glucosyltransferase that synthesizes alpha-1,6-glucan, and / or (ii) a glucosyltransferase that synthesizes alpha-1,3-glucan. Food products / precursors produced by this methodology are also disclosed.

The invention belongs to the technical field of oral care, and particularly relates to an oral care composition and a preparation method thereof. The composition for oral care is prepared from the following components in percentage by mass: 0.1 to 0.3 percent of chitosan oligosaccharide, 0.08 to 0.14 percent of hail vegetable polysaccharide, 0.07 to 0.12 percent of forskolin, 0.05 to 0.09 percent of corn bud extract, 1 to 3 percent of thickening agent, 40 to 50 percent of humectant and the balance of water. The oral care composition can effectively inhibit the activity of glucosyltransferase, inhibit the generation of glucan, interfere the formation process of dental plaque, and reduce the attachment sites of pathogenic bacteria in the oral cavity. The oral mucosa epithelial cells can be promoted to proliferate and repair, and oral mucosa injury can be repaired. In addition, all the components in the composition are matched for use, so that oral microbial flora can be balanced, meanwhile, the effect of inhibiting pathogenic bacteria is achieved, and the oral environment is improved.

This invention provides recombinant polynucleotides comprising nucleic acids encoding CYP76AD6 or related genes, and their use for the production of L-DOPA from tyrosine and for the treatment of dopamine-responsive disorders such as Parkinson's disease. This invention also provides recombinant polynucleotides comprising nucleic acids encoding CYP76AD1 and / or CYP76AD6, nucleic acids encoding DOPA 4,5-dioxygenase (DOD) such as beet DODA1, and in some cases, nucleic acids encoding betaine-related glucosyltransferases such as the four o'clock gene cyclic-DOPA 5-O-glucosyltransferase (cDOPA5GT), and their use for the production of betaine. Finally, this invention provides chimeric polypeptides, expression vectors, cells, compositions, and organisms (including plants), and their use in the various methods of this invention.

The present disclosure relates, in part, to addition of glucosyltransferase type enzymes for producing and / or modifying alpha-glucan type structures in dough such as bread dough. Such enzymes encompass various glucosyltransferases where these enzymes can transfer glucose from sucrose for production and / or modification of alpha-glucan type polymers in bread dough. Further disclosed are methods of preparing a baked food product by baking a dough, comprising incorporating into the dough one or more of the foregoing enzymes, wherein the enzyme can transfer a glucose-based moiety from sucrose to the non-reducing end of a saccharide acceptor, thereby improving texture, specific volume, dough stability, dough viscosity, anti-staling attributes and / or moisture content, for example.

The application discloses application of a tobacco zeatin glucosyltransferase gene in regulating tobacco seed germination time. The gene is NtZOG, the nucleotide sequence of which is shown as SEQ ID NO. 1, and the amino acid sequence of which is shown as SEQ ID NO. 2. Research finds that by knocking out the tobacco zeatin glucosyltransferase gene NtZOG from wild tobacco K326, a tobacco mutant with the NtZOG gene knocked out is constructed. By comparing the germination of the wild tobacco K326 and the mutant, it is found that the germination rate of the mutant is significantly lower than that of the wild tobacco at 4.5 days of development, and is as low as about 50%, so it can be seen that the tobacco zeatin glucosyltransferase gene NtZOG has an important regulating effect on tobacco seed germination, and the expression of the gene can be regulated to regulate the germination time of tobacco, and the application has a potential application prospect in the tobacco planting field.

The invention belongs to the field of enzyme engineering, and discloses a glycosyl transferase pgUGT-M8 mutant which is subjected to at least one of the following mutations on the basis of an amino acid sequence shown in SEQ ID NO.1: M87H, I146 F / Y / H / W / P / M / C, Y164 W / H / F / M / C, N178 H / W / Y, L182V and K207R. The activity of the mutant is greatly improved, compared with the initial UDP-glucosyltransferase mutant M8, the relative activity is maximally improved by 30 times, kcat / Km is improved by more than 30 times, and the mutant can be applied to synthesis of rebaudioside D.

The invention discloses a gamma-cyclodextrin glucosyltransferase mutant and application thereof, the mutant is obtained by mutating the 187th serine of wild gamma-CGTase from Candidate Angelobacter sp. Into alanine and mutating the 265th asparagine into phenylalanine, and the nucleotide sequence of the coding gene of the mutant is as shown in SEQ ID NO.7. The invention also discloses a preparation method of the gamma-cyclodextrin glucosyltransferase mutant. The invention also provides a recombinant expression vector containing the gene, a recombinant genetically engineered bacterium and application of the recombinant expression vector and the recombinant genetically engineered bacterium in preparation of gamma-cyclodextrin. Compared with wild gamma-CGTase, the relative enzyme activity of the mutant is improved by 1.8 times; after incubation at 60 DEG C for 2 hours, the residual enzyme activity is still kept at 85% or above; when the mutant is used for catalyzing starch to prepare gamma-cyclodextrin, the proportion of gamma-cyclodextrin in a product is not lower than 97%. Therefore, the gamma-cyclodextrin can be efficiently and highly selectively prepared only by taking the natural starch as the substrate, and a novel enzyme preparation and a process route which are efficient, stable and better in cost are provided for industrial production of the gamma-cyclodextrin.

Disclosed herein are methods of producing a food product or food precursor, for example. These methods can comprise: (a) providing a food product / precursor that comprises at least water and fructose, and (b) contacting the food product / precursor with an epimerase that converts fructose to a fructose epimer, wherein at least one fructose epimer is produced in the food product / precursor. A glucosyltransferase enzyme (GTF) can be further included with the epimerase for contacting the food product / precursor, for example. Food products and food precursors produced by this methodology are also disclosed.

The invention discloses a covalent immobilization method of an acid-resistant cyclodextrin glucosyltransferase mutant and an application of the acid-resistant cyclodextrin glucosyltransferase mutant in preparation of 2-O-alpha-D-glucopyranosyl-L-ascorbic acid. The surface of a solid carrier is subjected to functional modification, active groups such as carboxyl, sulfo or amino are introduced, and a carbodiimide coupling agent is adopted in an acidic buffer system for mediation, so that covalent bonding fixation of the acid-resistant cyclodextrin glucosyltransferase and the carrier is realized. The immobilization system is suitable for the condition that the pH value is 4.5-5.5, and the structural stability and the operation stability of the enzyme in an acid environment are remarkably improved. The immobilization system obviously enhances the structural stability and operation stability of the enzyme in an acid environment, and can be repeatedly used. The prepared immobilized enzyme shows high catalytic activity and high conversion rate in synthesis of AA-2G, and is suitable for continuous and efficient industrial production.

The invention belongs to the technical field of gene engineering and enzyme engineering, and particularly relates to a cyclodextrin glucosyltransferase mutant and application thereof in synthesis of gamma-cyclodextrin. The invention discloses a cyclodextrin glucosyltransferase mutant. The mutant is obtained by mutating one or more sites of serine at the 232 site, glycine at the 362 site, glycine at the 514 site and glycine at the 681 site of an amino acid sequence shown in SEQ ID NO. 2. Compared with wild cyclodextrin glucosyltransferase, the cyclodextrin glucosyltransferase mutant disclosed by the invention has the advantages that the enzyme activity and the thermal stability are obviously improved, and the performance of wild enzyme is optimized and improved; meanwhile, when the mutant is used for synthesizing the gamma-cyclodextrin, the yield of the gamma-cyclodextrin can be remarkably increased.

This invention proposes a UDP-glucosyltransferase mutant and a method for preparing rebaudioside D. Site-directed mutagenesis of UDP-glucosyltransferase is performed, and the mutant plasmid is transferred to *E. coli* to obtain recombinant engineered bacteria. The recombinant engineered bacteria express the protein through fermentation to obtain a crude enzyme solution of the UDP-glucosyltransferase mutant. ADP-dependent enzyme activity and temperature-dependent enzyme activity of the UDP-glucosyltransferase mutant were measured. The mutant ADP-dependent enzyme activity was significantly increased, and it exhibited thermostability. Rebaudioside D was prepared using rebaudioside A, sucrose, ADP, the UDP-glucosyltransferase mutant, and AtSUS sucrose synthase hypercatalytic synthase.

The invention provides UDP-glucose transferase for catalyzing glycosylation at C2'site of aescin, a gene, a primer group and application, and belongs to the technical field of aescin. The method is based on aesculus chinensis genome and transcriptome data analysis; according to the present invention, the UGT gene for catalyzing the C2'site of the protoaescinogenin-3-O-beta-D-glucopyranuronide is excavated, and the tobacco transient expression system is utilized to verify that the AcUGT94AK1, the AcUGT94AK3 and the AcUGT94AK6 can catalyze the protoaescinogenin-3-O-beta-D-glucopyranuronide to form the protoaescinogenin-3-O-beta-D-glucopyranuronide-(1-> 2)-beta-D-glucoside, such that the UGT gene can be used for catalyzing the C2 'site of the protoaescinogenin-3-O-beta-D-glucopyranuronide; the invention not only provides an important gene element for biosynthesis of aescin compounds, but also provides a key gene locus for molecular breeding of aesculus chinensis, and provides a theoretical basis for glycosylation modification of other triterpenoid saponins.

The invention discloses recombinant escherichia coli with high yield of cyanidin-3-O-glucoside as well as a construction method and application of the recombinant escherichia coli. The method comprises the following steps: by taking escherichia coli BL21 (DE3) engineering bacteria as a host, integrating flavanonol 4-reductase, anthocyanin synthetase and flavonoid 3-O-glucosyltransferase from different sources onto a plasmid vector pRSFDuet, and constructing to obtain a chassis cell for producing C3G; meanwhile, glutathione transferase is overexpressed, dissolution-promoting tag small ubiquitin-like modified protein is added, FaDFR is modified through enzyme engineering, FaDFR catalytic efficiency is improved through artificial protein cage space combination pathway enzyme, key precursor UDP-glucose is synthesized in an in-situ intensified mode and cofactor engineering, the cell factory for efficiently synthesizing C3G is constructed based on the combination strategy, the yield of C3G is increased, and the method has the advantages that the method is simple and convenient to operate, and the cost is low. The titer reaches 797.20 mg / L. The method provided by the invention has the characteristics of simplicity, economy and eco-friendliness.