1Department of Applied Biology and Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, Tokyo, 156-8502, Japan
Lipase of the intestine of Tilapia nilotica was purified by ammonium sulfate precipitation, followed by ion-exchange chromatography (DEAE-cellulose),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 177 times higher than that of the crude extract.
The lipase had a molecular weight of 46,000, showed the highest activity at pH7.5 and 35°C, and was stable at pH6.5-8.5 and below 40°C. The Km of the enzyme for olive oil was calculated to be 0.7mM. Its activity wasinhibited by Cu2+, Cd2+, Ni2+, Hg2+, PCMB, and CH2ICOOH.
This enzyme specifically digested Tributyrin and Tricaproin, whereas it digested 1,2-diolein and 1-monoolein more than 1,3-diolein and 2-monoolein. The enzyme well decomposed soybean oil and coconut oil.