PURIFICATION AND PROPERTIES OF AMYLASE FR OM TILAPIA STOMACH

Amylase of the stomach of Tilapia nilotica was purified by ammonium su lfate precipitation, followed by affinity chromatography (alpha-cyclod extrin-Sepharose 6B), chromatofocusing (polyexchanger PBE 94), and gel filtration (Sephadex G-75). The amylase was found to be a single band when examined by electrophoresis. The specific activity of the purifi ed enzyme was 54 times higher than that of the crude extract. The amyl ase had a molecular weight of 40,000, showed the highest activity at p H 6.0 and 35 degrees C, and was stable at PH 5.5-7.0 and below 45 degr ees C. The Km value of the enzyme for soluble starch was calculated to be 5.8 mg/ml. Its activity was inhibited by Hg2+, Pb2+, Cu2+, Zn2+, P CMB, and DTNB. This enzyme digested not only Polysaccharides such as s oluble starch, amylopectin, and amylose but also oligosaccharides such as maltotetraose, maltopentaose, and maltoheptaose.