56 results about "Isomerase activity" patented technology

The invention relates to a method for preparing immobilized glucose isomerase with composite magnetic chitosan microballoon spheres, which comprises the steps of: adding polyethylene glycol into FeCl2 and FeCl3, dissolving, regulating pH of solution to 8 to 10 with ammonia water, washing, filtering, freezing and drying in vacuum to obtain Fe3O4 magnetic nuclei, dissolving chitosan powder in acetic acid to carry out ultrasonic dispersion to prepare chitosan solution, carrying out ultrasonic dispersion and stirring on emulsifying agents and the Fe3O4 magnetic nuclei, crosslinking 1 to 5% glutaric dialdehyde at 2000 r/min, stirring, washing, filtering, freezing and drying in vacuum to obtain composite magnetic chitosan microballoon spheres, soaking the composite magnetic chitosan microballoon spheres with phosphate buffer pH of which is 7.0 to 7.8, filtering, adding glucose isomerase diluted by buffer, vibrating, taking out the glucose isomerase, putting the glucose isomerase in a refrigerator for one night, pouring off supernate, precipitating, washing, and filtering to obtain the immobilized glucose isomerase. In the invention, the glucose isomerase activity recovery ratio of which can reach more than 80% is immobilized by the composite magnetic chitosan, and has high service efficiency, reusability and low cost.

The production of carotenoid is accomplished using a DNA molecule that encodes a polypeptide as obtained from Haematococcus pluvialis, Phaffia rhodozyma, or Saccharomyces cerevisiae, having isopentonyl pyrophosphate (IPP) isomerase activity, or DNA molecule having a nucleotide sequence that hybridizes thereto. In particular, one can introduce such a DNA molecule into a carotenoid-producing microorganism, culture the microorganism thus transformed, and then obtain carotenoids in the culture broth and cells.

The present invention utilizes the construction of dasytis akajei caudal spine cDNA library and DNA sequencing and designs the primer according to the obtained (CyP) EST 3' end and carrier nucleotide sequence, and uses PCR method to screen the dasytis akajei caudal spine cDNA library and clone the cyclophilin A total strength gene. The tength of new gene is 656 bp for coding mature peptide of 167 amino acids, the isoelectric point of the expressed protein is 8.34, and the molecular weight is 18,021 Dalton. The dasytis akajei caudal spine cyclophilin A gene is cloned in the uxA gene 3' tail end of thioredoxing gene fusion expression vector pTRX and the fusion gene meeting reading frame is construcled, said fusion protein is existed in colibacillus, its expression amount can be up to 60 mg/L.

The invention belongs to the technical field of enzyme engineering, and discloses a D-psicose-3-epimerase active aggregate as well as a preparation method and application thereof. The D-psicose-3-epimerase active aggregate comprises D-psicose-3-epimerase and a self-aggregation oligopeptide, so that the reaction temperature of the D-psicose-3-epimerase can be increased, and the half-life period of the D-psicose-3-epimerase can be prolonged; the dependence on metal ions is obviously reduced; and the reutilization frequency is increased.

The invention belongs to the technical field of biochemistry, and particularly relates to a quinoxaline-N1,N4-dioxide derivative capable of inhibiting the activity of DNA topoisomerase, a preparationmethod and application of the quinoxaline-N1,N4-dioxide derivative. 4,5,-difluoro-2-nitroaniline is used as a raw material for synthesis of the quinoxaline-N1,N4-dioxide derivative, the quinoxaline-N1,N4-dioxide derivative reacts with sodium hypochlorite under catalysis of a basic catalyst, namely sodium hydroxide, and 5,6-difluoro-N-benzofuroxan is obtained; and then the quinoxaline-N1,N4-dioxidederivative reacts with different substrates in Beirut reaction and substitution reaction, and a series of the quinoxaline-N1,N4-dioxide derivative is obtained. According to the quinoxaline-N1,N4-dioxide derivative, the preparation method and application of the quinoxaline-N1,N4-dioxide derivative, quinoxoline-N1,N4-dioxide has good bacteriostatic activity to previously reported gram-negative bacteria, and also had good bacteriostatic activity to actinobacilluspleuropneumoniae and gram-positive bacteria such as staphylococcus aureus and streptococcus pneumoniae.

The present disclosure relates to a method for preparing recombinant glycoproteins with high sialic acid content. More specifically, for UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE/MNK) enzyme where point mutation was induced by substituting arginine at position 263 by leucine only or by further substituting arginine at position 266 by glutamine, epimerase activity is constantly maintained, and overexpressed cells thereof experience an increase in intracellular cytidine monophosphate (CMP)-sialic acid content, irrespective of CMP-sialic acid concentration.,Particularly, since in an glycoprotein(such as, erythropoietin and thrombopoietin)-producing host cell where point mutationinduced GNE/MNK, human alpha-2,3-sialyltransferase and a CMP-sialic acid transporter gene are simultaneously overexpressed, intracellular content of CMP-sialic acid and sialic acid in glycoprotein increases in cells, overexpression in a host cell producing a sialylated recombinant glycoprotein the three genes above may be useful for preparing glycoprotein with increased sialic acid content.

The invention discloses a fat-soluble glabridin compound whitening agent and application of the agent in cosmetics. The compound whitening agent is prepared from the following active ingredients in byweight percent: 30-50 percent of glycyrrhiza glabra extract, 10-30 percent of tetrahydroxychalcone, 10-30 percent of ubiquinone and 10-30 percent of an endothelin antagonist. The compound whitening agent has main whitening action mechanisms of inhibiting the activity of tyrosinase, inhibiting the activity of DOPA chrome tautomerase and obstructing indole-5,6-quinone polymerization, so that melanogenesis can be obstructed, differentiation of melanophores can be reduced, and the aims of whitening skin, lightening spots and improving dark skin color can be achieved. The compound whitening agenthas a simple and practical formula and a good whitening and spot-lightening effect, is environmentally friendly and safe since natural products are adopted, is mild and nonirritant in use, and can overcome the defect in an existing whitening agent.

This invention provides a novel gene that can impart salt stress tolerance to plants for a long period of time and salt stress tolerant transgenic plants to which such gene has been introduced. Such novel gene encodes the following protein (a), (b), or (c), and such salt stress tolerant transgenic plant has such gene introduced therein: (a) a protein consisting of the amino acid sequence as shown in SEQ ID NO: 2 in the Sequence Listing; (b) a protein consisting of an amino acid sequence derived from the amino acid sequence as shown in SEQ ID NO: 2 in the Sequence Listing by deletion, substitution, or addition of one or several amino acid residues and having activity of imparting salt stress tolerance to plants; or (c) a protein consisting of an amino acid sequence derived from the amino acid sequence as shown in SEQ ID NO: 2 in the Sequence Listing by deletion, substitution, or addition of one or several amino acid residues and having UDP-glucose 4-epimerase activity.

The invention discloses eggplant chalcone isomerase SmCHI protein and a coding gene thereof. The protein comprises (a) protein consisting of an amino acid sequence as shown in SEQ ID NO.3; or (b) protein derived from the amino acid sequence in (a), which is substituted, lost or added by one or more amino acids and has the activity of eggplant chalcone isomerase. The cDNA and gDNA of the coding gene respectively have base sequences as shown in SEQ ID NO.1 and SEQ ID NO.2; and the gene is expressed in roots, stems, leaves, flowers, peels and pulp, and has the expression quantity in peels remarkably higher than that in other tissues. Under stress of low temperature, the expression quantity of the gene reaches the maximal value in 48 hours, which is 3.65 times that of an unprocessed gene. The eggplant chalcone isomerase SmCHI protein and the coding gene thereof provide a theoretical basis for improving plant quality by utilizing the genetic engineering technology to obtain high oxidation resistance medicines or foods in the future, thereby having great application values.

There are provided a DNA coding for phosphohexuloisomerase, which is a protein defined in the following (A) or (B), and a method for producing the enzyme: (A) a protein having the amino acid sequence of SEQ ID NO: 3 shown in Sequence Listing, (B) a protein having the amino acid sequence of SEQ ID NO: 3 shown in Sequence Listing including substitution, deletion, insertion or addition of one or several amino acid residues and having phosphohexulose isomerase activity.

The present invention belongs to biotechnology, and the intracellular analysis and detection process of peptidyl-propyl-cis/trans isomerase activity includes constructing fusion gene through fusion of protein or polypeptide, which contains X-Pro bond and realizes correct folding via cis/trans isomerization under PPIases catalysis, with green fluorescent protein (GFP); expressing fusion protein; fluorescent observation of the green fluorescence of GFP; and indicating and analyzing the activity of PPIases inside microbe, plant and animal cell. The said process may be used in PPIases activity detection inside live cell, and the GFP fluorescence may be observed directly with fluorescent microscope to determine intracellular PPIases activity simply, flexibly and intuitively. The cell introduced into fusion gene may be used directly as the type culture for relevant PPIases research and the type culture may be proliferated and propagated via microbe and cell culturing process for long termuse.

In the rare sugar strategy of Izumoring (FIG. 1), it is intended to establish a reaction system of producing rare sugars of many types by acquiring an isomerase which acts on various rare aldoses and, therefore, is most efficient in producing various rare ketoses. A DNA encoding the following protein (a) or (b). The above-mentioned DNA which is L-rhamnose isomerase derived from Pseudomonas stutzerii. A protein comprising the amino acid sequence represented by SEQ ID NO:2. A process for producing a recombinant protein characterized by culturing a host cell containing an expression system that can express the above-mentioned protein in a medium and collecting a recombinant protein having an L-rhamnose isomerase activity from the thus obtained culture. A method of applying FIG. 1 to the production of a rare sugar characterized in that the location of a target rare sugar in the overall picture of monosaccharides is understood and thus the optimum production pathway on which the above protein is allowed to act is designed.

Methods are provided for obtaining a genetically modified plant, wherein the plant exhibits an increased oil yield relative to a corresponding control plant that is not so genetically modified. The methods comprise genetically modifying a plant progenitor cell to cause a decrease in triose-phosphate isomerase activity and an increase in glycerol-3-phosphate dehydrogenase activity. The methods also comprise culturing the genetically modified plant progenitor cell to obtain the genetically modified plant. Also provided are methods for increasing oil yield, comprising genetically modifying a plant to cause, in at least one oil-producing organ or tissue of the plant, a decrease in triose-phosphate isomerase activity and an increase in glycerol-3-phosphate dehydrogenase activity. The genetic modification is carried out across more than a single generation. The genetically modified plant exhibits an increased oil yield relative to a corresponding control plant. Also provided are similar methods directed to a microbe.

The invention is in the field of enzymology. More in particular, it provides a method for the isomerization of glucose into fructose wherein the glucose is derived from lignocellulosic material. More in particular, the invention provides polypeptides encoding mutant glucose isomerase enzymes with improved glucose isomerase activity as compared to the corresponding wild type enzyme. The disclosed polypeptides are particularly suited for converting glucose to fructose in the presence of xylose.

The invention relates to a method for rapidly measuring the activity of epimerase by using a circular dichroism spectrum. According to the method, epimerase is added into a dipeptide enantiomer initial solution for catalytic reaction; a CD signal intensity change of the dipeptide enantiomer solution before and after the catalytic reaction is detected by using a circular dichroism spectrum; if anychange happens, the epimerase is indicated to have activity; and otherwise, e epimerase is indicated not to have activity. According to the method provided by the invention, no derivative reaction isneeded; the operation is simple, the reproducibility is high, the error range is small, the sensitivity is high, the linear range is wide, and measurement can be carried out continuously, and in-situdetection can be realized. Therefore, a new field is provide for research on chiral recognition.