Enzymes That Hydrolyze Fungal Cell Wall Polysaccharides

An endo-α-d-(1 → 3)-glucanase capable of hydrolyzing various α-(1 → 3)-glucans has been isolated and purified from the culture filtrate of the cellulolytic fungus Trichoderma viride, and its specificity has been examined. Of the compounds tested only those with α-(1 → 3)-glucosidic linkages were attacked, and the enzymatic hydrolysis occurred with retention of configuration of the anomeric carbon atom involved in cleavage. Some properties of the enzyme have been investigated. Optimum pH and temperature for activity are 4.5 and 50°, respectively. The values of Km and Vmax under standard assay conditions are 4.6 x 10-2 m glucose equivalents and 0.16 µmole of glucose equivalent per min. The molecular weight of the enzyme estimated by column chromatography on Sephadex G-100 was found to be approximately 47,000. Zn++ and Fe++ were found to be reversible inhibitors of the enzyme while Ag+ and Hg+ abolished activity irreversibly. The use of this enzyme in structural carbohydrate chemistry is discussed.