12 results about "Sucrose synthase" patented technology

The purpose of the present invention is to provide: a plant having an increased yield of storage tissue; and a method for producing the plant. It was discovered that the yield of storage tissue in a plant can be increased by expressing, in the storage tissue of the plant, a sucrose synthase having a substrate specificity to adenosine diphosphate.

The application discloses a sucrose synthetase mutant and a method for preparing RD by using the sucrose synthetase mutant, wherein the sucrose synthetase mutant contains at least one of the following mutations: D296Q, R636Q, G514L, H531L, R567T, D569Q, E610N, A642N, E663N, L667T and T742R on the basis of the amino acid sequence shown in SEQ ID NO:2; the sucrose synthetase mutant has higher enzyme activity than the wild type, and meanwhile, some mutants still maintain a high conversion rate in a wider pH range.

The utility model discloses a kind of multi-enzyme step-by-step preparation glucosyl steviol glycoside's device, it is related to glucose steviol glycoside production technical field, the inlet of first reaction tank is respectively communicated with raw material tank, dextrin tank, cyclodextrin glucoside transferase tank and first sodium hydroxide solution tank, the outlet of first reaction tank is communicated with hydrolysis tank, the outlet of hydrolysis tank is communicated with second reaction tank, the inlet of second reaction tank is respectively communicated with sucrose tank, sucrose synthase tank, uridine diphosphate tank, UGT glycosyltransferase tank and lye tank, the outlet of second reaction tank is communicated with concentration tank by pipeline, the lower outlet of concentration tank is communicated with drier, the outlet of drier is communicated with glucosyl steviol glycoside tank. Make residual substrate conversion is relatively more optimal steviol glycoside in taste, improve the taste, quality and yield of product.

The present disclosure provides enzymes and methods of using those enzymes to transfer sugar moieties to substrate steviol glycosides. Specifically, designed beta-1,2-glycosyltransferases and sucrose synthases are used in one-pot reactions to convert stevioside and Reb A to Reb E and Reb D. Additionally, designed beta-1,2-glycosyltransferases can be used in one-pot reactions with sucrose synthases and beta-1,3-glycosyltransferases to produce Reb M from stevioside and / or Reb A.

This invention belongs to the fields of genetic engineering and enzyme engineering, specifically relating to a sucrose synthase mutant, its preparation method, product, and application. The mutant is based on the amino acid sequence of the wild-type sucrose synthase shown in SEQ ID NO.1, with the 94th amino acid mutated from P to N, resulting in the amino acid sequence shown in SEQ ID NO.2; or the 660th amino acid mutated from Y to H, resulting in the amino acid sequence shown in SEQ ID NO.3. This mutant can be used for in vitro glycosylation reactions, plant genetic improvement, or industrial biocatalysis, solving the technical problems of poor stability and low catalytic efficiency of natural enzymes.

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.

Disclosed in the present invention are a sucrose synthase mutant and a method for preparing RD using same. The sucrose synthase mutant is based on the amino acid sequence shown in SEQ ID NO: 2 and contains a mutation in at least one of the following sites: D296Q, R636Q, G514L, H531L, R567T, D569Q, E610N, A642N, E663N, L667T and T742R. By means of site-directed mutagenesis of sucrose synthase, the enzyme activity of the sucrose synthase mutant is improved compared with that of the wild type. Also, some mutants can still maintain a high conversion rate in a wide pH range.

The present application relates to the technical field of traditional Chinese medicine processing, and particularly relates to a processing method for regulating the quality of Yunnan rhizoma polygonati by stress, which uses fresh Yunnan rhizoma polygonati as raw material, and adopts a programmed temperature control method to perform stress, washes, processes, slices and dries the stressed Yunnan rhizoma polygonati to obtain a finished product; the stress is heat stress or cold stress. Compared with the prior art, the present application gradually changes the stress of the collected fresh Yunnan rhizoma polygonati, avoids the damage to the physiological structure of the plant caused by the rapid change or large amplitude of the temperature, and thus affects the ability and efficiency of the plant to secrete secondary metabolites. The present application significantly increases the polysaccharide content of Yunnan rhizoma polygonati from the source production site processing link, improves the activity of sucrose synthase, and improves the quality of Yunnan rhizoma polygonati. The present application is simple and easy to operate, and provides a new idea for the new production site processing method of medicinal Yunnan rhizoma polygonati.

To provide a plant with increased yield of storage tissue and a method for producing the same. [Solution] In the storage tissue of a plant, a sucrose synthase that has substrate specificity for adenosine diphosphate is expressed, thereby increasing the yield of the storage tissue of the plant.

A method for preparing fucose and intermediates thereof and applications thereof. In the method for synthesizing GDP-fucose, GDP-fucose is generated by catalytic reaction of sucrose synthase, CDP-threose 2-epimerase, GDP-mannose dehydratase and isomerase with guanosine diphosphate and sucrose as substrates. In the method for synthesizing fucosyllactose, fucosyllactose is obtained by catalytic action of Hp13FucT2 enzyme with GDP-fucose and pNP-lactose as initial substrates. In the method for preparing L-fucose by enzyme, L-fucose is generated by catalytic reaction of fucosidase with fucosyllactose as substrate. The E. coli expression system has the characteristics of high expression efficiency, large expression amount, low cost and easy operation, and the expressed fucosidase has the advantages of high purity and high yield.

The application discloses a glycosyltransferase Ml CGT and mutants thereof and application thereof in preparing luteolin-3'-O- O glucoside, and belongs to the technical field of biological catalysis and natural product synthesis. Ml The application constructs a glycosyltransferase CGT mutant, which shows high regioselectivity for luteolin and can be used for preparing luteolin-3'-O- O glucoside in a directional conversion mode, the conversion rate reaches 99%, and the catalytic efficiency is 5203.2 L·mol ‑1 ·s ‑1 , which is significantly higher than that of the wild-type enzyme. At The application further constructs a cascade catalysis system comprising the mutant and sucrose synthase SUS1, and realizes in-situ regeneration of UDP-glucose. O By optimizing the UDP concentration, sucrose concentration, temperature and pH conditions, the conversion rate of luteolin-3'-O- O glucoside is further improved, and the yield can reach 90%, so that the application has the application potential in large-scale biological preparation of luteolin-3'-O- glucoside.

This invention belongs to the field of enzyme engineering, specifically relating to a thermostable sucrose synthase mutant and its applications. Based on the amino acid sequence of sucrose synthase shown in SEQ ID NO:1, this invention utilizes rationally designed molecular modification techniques to perform site-directed mutagenesis, resulting in a significantly improved thermostability of the modified sucrose synthase mutant. The mutant enzyme was obtained by inducing expression and purifying the protein from the resulting mutant strain. Compared to the wild-type sucrose synthase, the mutant exhibits a half-life that is extended from 42.88 min to 679.41 min at 50°C, which is 15.8 times that of the wild-type; and at 55°C, the half-life is increased from 12.94 min to 110 min, reaching 8.5 times that of the wild-type, thus better suited for industrial production.