3767-28-0Relevant articles and documents
Glucoamylase originating from Schwanniomyces occidentalis is a typical α-glucosidase
Sato, Fumiaki,Okuyama, Masayuki,Nakai, Hiroyuki,Mori, Haruhide,Kimura, Atsuo,Chiba, Seiya
, p. 1905 - 1913 (2005)
A starch-hydrolyzing enzyme from Schwanniomyces occidentalis has been reported to be a novel glucoamylase, but there is no conclusive proof that it is glucoamylase. An enzyme having the hydrolytic activity toward soluble starch was purified from a strain of S. occidentalis. The enzyme showed high catalytic efficiency (kcat/Km) for maltooligosaccharides, compared with that for soluble starch. The product anomer was α-glucose, differing from glucoamylase as a β-glucose producing enzyme. These findings are striking characteristics of α-glucosidase. The DNA encoding the enzyme was cloned and sequenced. The primary structure deduced from the nucleotide sequence was highly similar to mold, plant, and mammalian α-glucosidases of α-glucosidase family II and other glucoside hydrolase family 31 enzymes, and the two regions involved in the catalytic reaction of α-glucosidases were conserved. These were no similarities to the so-called glucoamylases. It was concluded that the enzyme and also S. occidentalis glucoamylase, had been already reported, were typical α-glucosidases, and not glucoamylase.
Substrate and preparation method and application thereof
-
Paragraph 0027; 0028, (2019/05/15)
The invention discloses a substrate namely alpha-D-glucoside for detecting activity of alpha-glucosidases, and further discloses a synthesis technology of the substrate. The synthesis technology comprises the steps of enabling a compound alpha-D-glucose and acetyl chloride to be subjected to a reaction, and performing purification to obtain alpha-D- pentacetylglucose; catalyzing the obtained substances with N,N-Dimethyl-1,3-diaminopropane, performing pickling, performing extraction, performing drying, and performing purifying to obtain 2,3,4,6-tetra-O-acetyl-alpha-D-acetyl-glucosamine; catalyzing the obtained substances in a dichloromethane solution, performing a reaction with trichloroacetonitrile, performing filtering, and performing purifying to obtain 2,3,4,6-tetra-O-acetyl-beta-D-glucosyl trichloroacetimidate; performing catalyzing on the obtained substances in a dichloromethane solution, performing a reaction with chromogen or fluorophore, performing extraction, merging organic phases, performing drying, performing concentrating, performing methanol redissolution, performing crystal nourishing at 4 DEG C, and performing filtering to obtain 2,3,4,6-tetra-O-acetyl-alpha-D-glucoside; and catalyzing the obtained substances in a methanolic solution, performing a reaction, then performing decoloring adsorption, performing filtering, and performing purifying. The synthesis technology of the substrate is simple and high in yield, the sensitivity of a reagent kit can be improved, the stability is good, and the specificity is high.
Purification, characterization, and gene identification of an α-glucosyl transfer enzyme, a novel type α-glucosidase from Xanthomonas campestris WU-9701
Sato, Toshiyuki,Hasegawa, Nobukazu,Saito, Jun,Umezawa, Satoru,Honda, Yuki,Kino, Kuniki,Kirimura, Kohtaro
body text, p. 20 - 27 (2012/09/05)
The α-glucosyl transfer enzyme (XgtA), a novel type α-glucosidase produced by Xanthomonas campestris WU-9701, was purified from the cell-free extract and characterized. The molecular weight of XgtA is estimated to be 57 kDa by SDS-PAGE and 60 kDa by gel filtration, indicating that XgtA is a monomeric enzyme. Kinetic properties of XgtA were determined for α-glucosyl transfer and maltose-hydrolyzing activities using maltose as the α-glucosyl donor, and if necessary, hydroquinone as the acceptor. The Vmax value for α-glucosyl transfer activity was 1.3 × 10-2 (mM/s); this value was 3.9-fold as much as that for maltose-hydrolyzing activity. XgtA neither produced maltooligosaccharides nor hydrolyzed sucrose. The gene encoding XgtA that contained a 1614-bp open reading frame was cloned, identified, and highly expressed in Escherichia coli JM109 as the host. Site-directed mutagenesis identified Asp201, Glu270, and Asp331 as the catalytic sites of XgtA, indicating that XgtA belongs to the glycoside hydrolase family 13.
