PRODUCTION AND CHARACTERISTICS OF AN INTRACELLULAR ALPHA-GLUCOSIDASE FROM A COLOR VARIANT STRAIN OF AUREOBASIDIUM-PULLULANS

Aureobasidium pullulans produced an intracellular alpha-glucosidase. T he enzyme was purified 124-fold by solubilization with Triton X-100, Q -Sepharose treatment, hydroxylapatite, octyl-Sepharose column chromato graphy, and gel filtration on Sephacryl S-200, and had a specific acti vity of 316.82 U/mg protein. The enzyme displayed an optimum pH for it s action at 4.0 and was fully stable at pH 3.0-6.0 at 50-degrees-C. Th e alpha-glucosidase was completely stable up to 60-degrees-C and had a n optimum activity at 60-degrees-C. The partially purified enzyme prep aration hydrolyzed maltose, isomaltose, sucrose, and trehalose at rela tive rates of 100, 60, 47, and 50, respectively, and had little or no activity on polysaccharides. The K(m) value for maltose hydrolysis at pH 4.0 and 50-degrees-C was 1.85 mm. The enzyme was not adsorbed onto raw corn starch and showed little raw starch degradation. The a-glucos idase did not require any metal ion for activity. This represents the first characterization of intracellular a-glucosidase from A. pullulan s.