6092-25-7Relevant academic research and scientific papers
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.
