Studies on mannanase of Streptomyces. Part III. Purification and some properties of mannanase from Streptomyces sp.

Abstract

Four mannanases (Mannanases I, II, III, and IV) were isolated from the culture filtrate of a Streptomyces sp. by ion exchange chromatography. Mannanase IV was the main component and accounted for 64.4% of the total activity of the four mannanases. Mannanase IV was further purified by gel filtration, and the purified Mannanase IV was homogeneous on disc-gel electrophoretic analysis. Optimum pH and temperature for the activity of Mannanase IV were 6.8 and 57°C, respectively. It was stable at temperatures up to 45°C when examined at pH 6.8 for 30 min, and lost only 15% of its activity at 70°C for 30min at pH 6.8. The isoelectric point and molecular weight were pH 3.65 and 42, 900, respectively. The enzyme was strongly inactivated by Al3+, Hg2+, Fe2+, Fe3+, Cd2+, Ag+, Sn2+, and Cu2+, and completely inhibited by iodoacetic acid and N-bromosuccinimide. The enzyme hydrolyzed mannotriose to mannose and mannobiose, but did not hydrolyze mannobiose.