Purification of an Exo-β-d-(1 → 3)-glucanase from Basidiomycete Species QM 806

Abstract

Abstract An exo-β-d-(1 → 3)-glucanase has been purified from the culture medium of Basidiomycete species QM 806. The purification involves evaporation of the culture filtrate, ammonium sulfate fractionation, column chromatography, and preparative acrylamide gel electrophoresis. The final preparation is homogeneous on the basis of disc electrophoresis on acrylamide gel, sedimentation in the ultracentrifuge, and the absence of contaminating enzymatic activities. Various physical and chemical characteristics of the purified protein have been determined; a complete amino acid analysis is presented. The kinetic parameters, Km and V, of the action of the enzyme on a homologous series of β-d-(1 → 3)-linked glucose oligosaccharides have been determined. These indicate that the extent of binding and rate of attack increase rapidly with chain length but do not appear to reach maximal values even at a chain length of 15 to 20 glucose units.