Purification and Characterization of a<i>β</i>-Glucosidase from<i>Polygonum tinctorium</i>, Which Catalyzes Preferentially the Hydrolysis of Indican

Abstract

An enzyme, β-glucosidase, which hydrolyzes indican (indoxyl-β-D-glucoside) was isolated in pure form from a plant, Polygonum tinctorium, and characterized. The enzyme showed specifically a low Km for indican (0.34 mM). The enzyme reacted with some other β-glucosides having aromatic groups but not with α-glucoside or other glycosides like galactoside. The activity was inhibited by several metal cations such as Cu2+ and by typical inhibitors for β-glucosidase such as D-glucono-1,5-lactone although these inhibitors required high concentrations.