Purification, Crystallization, and Some Properties of Endo-poly-galacturonase from Aureobasidium pullulans

A new polygalacturonase was found in a culture filtrate of Aureobasidium pullulans. The enzyme was purified and obtained in crystalline form with 10% recovery. The crystalline enzyme was a homogeneous protein by analyses by sedimentation and electrophoresis. The enzyme was most active around pH 4.5, and stable in the pH range of 4 to 6. Its molecular weight was 42,000 and its isoelectric point was pH 6.0. The enzyme was an endo-polygalacturonase, catalyzing the cleavage of glycosidic bonds of polygalacturonic acid at random.The enzyme had less protopectinase activity than those of the endo-polygalacturonases that were isolated as protopectin-solubilizing enzymes from Trichosporon penicillatum, Kluyveromyces fragilis, and Galactomyces reessii. Some characteristics were compared with the endo-polygalacturonases, which have potent protopectinase activity.