33 results about "Enzymes levels" patented technology

The invention discloses a construction method and application of a recombinant bacterium producing chitosanase. The invention co-expresses the Bacillus subtilis chitosanase gene and the hyaline hemoglobin gene in Pichia pastoris, and the recombinant strain efficiently prepares the chitosanase through a high-density fermentation strategy. The enzyme activity of the chitosanase prepared by the method is as high as 50000 U / mL, and the protein content is as high as 16.0 mg / mL. The specific enzyme activity of the recombinant enzyme is 4065.7U / mg, the optimum pH is 6.0, and the optimum temperature is 55°C. The enzyme hydrolyzes high-concentration (≥10%) chitosan to prepare chitosan oligosaccharides, the chitosan oligosaccharide yield is greater than 75%, and the main products are disaccharides, trisaccharides and tetrasaccharides. The chitosanase preparation method of the present invention produces enzyme level far higher than the reports of existing documents and patents, and the produced enzyme has excellent hydrolysis characteristics, and has good performance in industrial production of chitosanase and preparation of chitosan oligosaccharides. application value.

The invention discloses a naphthenic-base mono substituted amino fluorescein compound as well as a preparation method and application thereof. The naphthenic-base mono substituted amino fluorescein compound has a structural general formula (described in the specification) or a free form thereof, wherein n is 0-9, and m is 1-9; when n is equal to m, R is mono substituted groups such as a hydrogen group, methyl, ethyl, propyl and halogen; and when n is not equal to m, R is the hydrogen group. The naphthenic-base mono substituted amino fluorescein compound can be used for detecting distribution and imaging of luciferase in vitro, cells and vivo by detecting the presence and quantity (including enzyme level, cellular level and animal level) of the luciferase by virtue of bioluminescence, can be also used for detecting distribution and imaging of ATP in vitro, cells and vivo by detecting the presence and quantity (including enzyme level, cellular level and animal level) of ATP and can be used for detecting pharmacological action of a medicine in enzyme level, cellular level and animal level as a report signal in the presence of luciferase, ATP and Mg<2+>.

The invention relates to an amino acid-fluorophore compound and application of the compound, wherein the general structural formula of the amino acid-fluorophore compound is (I), (II), (III), and (IV) or a free form thereof, wherein R1 is selected from various amino acid side chains, preferably methyl, propyl, 2-methylthio ethyl, benzyl, phenylethyl, 2-cyclohexyl ethyl, 4-isopropyl phenyl and 4-dimethyl amino phenyl; R2 is selected from various fluorophores, preferably 7-hydroxyl coumarin, naphthalimide fluorophores, Nile red series and Cy fluorophores; and X is C or N. Fluorescent probe molecules can be used for detecting the activity (enzyme level and cell level) of aminopeptidase N, can be used as a probe tool for detecting the tissue distribution of aminopeptidase N and tumor tissue imaging, and can be used as a diagnosis tool for various diseases due to abnormal expression of aminopeptidase N. In addition, the preparation method of the compound has the advantages of mild reaction conditions, easily-accessible and cheap raw materials and simplicity in operation and after-treatment.

The invention discloses the application of Haloferula sp.β-N-acetylhexosaminidase in synthesizing human milk oligosaccharides. The present invention provides the application of HaHex74 protein or its related biological materials in any of the following: (a1) synthesis of human milk oligosaccharides; (a2) synthesis of lactose-N-triose II and / or lactose-N-neotetrasaccharide; The HaHex74 protein is derived from Haloferula sp., and its amino acid sequence is shown in SEQ ID No.1. The β-N-acetylhexosaminidase of the present invention has high enzyme production level, excellent hydrolysis characteristics and high transglycoside transfection activity, and has important application value in enzymatically synthesizing human milk oligosaccharides.