Purification and Properties of an Endo β-1, 6-Glucanase from Rhizopus chinensis R-69

An endo β-1,6-glucanase (β-1,6-glucan glucanohydrolase, E, C. 3. 2. 1.) has been purified from the culture filtrate of a strain resembling Rhizopus chinensis in homogeneous form. The procedures involved ammonium sulfate fractionation followed by column chromatography of DEAE-cellulose, CM-Sephadex C–50 and BioGel P–60.Various physicochemical and chemical characteristics of the enzyme have been made clear, including complete amino acid composition. Optimum pH, optimum temperature, apparent activation energy for activity, Km and Vmax are 5.5~6.0, 60°C, 4.39 Cal per mole, 9.39×10‒3m glucose equivalents (0.169%) and 43.13 International Units, respectively. The enzyme required no metal ions for its activity, and it hydrolyzed β-1,6-glucan larger than gentiotetraose, forming gentiobiose and gentiotriose as main products.