Purification and characterization of a β-glucosidase from <i>Streptomyces lividans</i> 66

Abstract

An intracellular β-1, 4-D-glucosidase (EC 3.2.1.21) was isolated from the mutant strain HP-3 of Streptomyces lividans 66 which produced about 12 times more enzyme than the wild-type strain. The purification was carried out by anion exchange column chromatography followed by high-performance liquid chromatography on DEAE and on molecular sieve columns. The enzyme is glycosylated and has an apparent M r of 51 000 and a pI of 4.3. Its activity was optimal at pH 6.5 and at a temperature of 40 °C. The K m and the V max on cellobiose were 3.1 mM and 65.6 μmol min −1 mg −1 of enzyme. Key words: β-glucosidase, Streptomyces lividans, purification, characterization.