Isolation and Characterization of Two β-D-Glucosidases from Bifidobacterium breve 203

抄録

Two β-D-glucosidases were purified to homogeneity from Bifidobacterium breve 203: one β-D-glucosidase I; molecular weight, 96, 000) showed reactivity toward p-nitrophenyl (p-NP) β-D-fucoside, 74% of that to p-NP β-D-glucoside, and the other (β-D-glucosidase II; molecular weight, 450, 000) did not. They also differed in their thermal and pH stabilities. Laminaribiose, cellobiose and gentiobiose were hydrolyzed by β-D-glucosidase I, with 53%, 34% and 3% of the reactivity in the case of p-NP β-D-glucoside, and by β-D-glucosidase II, with 53%, 6% and 107% of the reactivity. The reaction of β-D-glucosidase I with p-NP β-D-fucoside was enhanced by the addition of glucose and other monosaccharides to the reaction mixture, whereas that with p-NP β-D-glucoside was not affected. The activity of β-D-glucosidase II with p-NP β-D-glucoside was inhibited by glucose.