Glucanases in Schizosaccharomyces. Isolation and properties of an exo-β-glucanase from the cell extracts and culture fluid of Schizosaccharomyces japonicus var. versatilis

Abstract

1. (1)|Cell extracts and extracellular culture fluids of species of the yeast genus Schizosaccharomyces exhibited exo-β-(1 → 3)- and exo-β-(1 → 6)-glucanase (EC 3.2.1.-) activities. 2. (2)|Using a combination of Sephadex G-100 and DEAE-cellulose chromatography, the exo-β-(1 → 3)-glucanases from the cell extracts and culture fluid of Schizosaccharomyces japonicus var. versatilis were purified extensively. The enzymes from either location exhibited similar purification and other properties. 3. (3)|The purified enzymes hydrolysed the β-(1 → 6)-glucosidic linkage in addition to the β-(1 → 3) linkage. Heat denaturation, inhibition and electrophoretic studies indicated that both hydrolytic activities were the properties of a single protein. Laminarin and pustulan hydrolysis followed Michaelis-Menten kinetics. The K m and V for laminarin hydrolysis were 6.25 mg/ml and 350 μmol of glucose released/min/mg protein, and for pustulan they were 166 mg/ml and 52 μmol of glucose released/min/mg protein. 4. (4)|The exo-β-glucanase was assigned a molecular weight of 43 000. 5. (5)|The purified enzyme failed to hydrolyse isolated cell walls from either baker's yeast or Schizosaccharomyces pombe or to induce protoplast formation from intact cells of S. japonicus var. versatilis or Saccharomyces cevisiae.