Purification and Properties of Lipase from Tilapia Stomach : Digestive Enzyme of Tilapia VII

Abstract

Lipase of the stomach of Tilapia nilotica was purified by ammonium sulfate precipitation, followed by chromatofocusing (Polyexchanger PBE 94), and gel filtration (Sephadex G-100). The lipase was found to be a single band when examined by electrophoresis. The specific activity of the purified enzyme was 19 times higher than that of the crude extract. The lipase had a molecular weight of 54, 000, showed the optimum activity at pH6.5 and 40°C, and was stable at pH5.0-7.0 and below 50°C. The Km of the enzyme for olive oil was calculated to be 0.6mM. Its activity was inhibited by Cu²⁺, Cd²⁺, Pb²⁺, Hg²⁺, Ni²⁺, PCMB, and EDTA. This enzyme hydrolyzed triacylglycerol more than diacylglycerol and monoacylglycerol. The enzyme hydrolyzed soybean oil well.