Staphylococcus haemolyticus lipase: biochemical properties, substrate specificity and gene cloning

Abstract

Lipase of Staphylococcus haemolyticus L62 was purified from culture supernatant and its molecular mass was estimated to be 45 kDa by SDS-PAGE. Its optimum temperature and pH for the hydrolysis of olive oil was 28°C and pH 8.5, respectively. The enzyme was stable up to 50°C in the presence of Ca2+and over the pH range 5-11. It had high hydrolytic activity against tributyrin, tripropionin, and trimyristin among various triglycerides. The gene encoding the lipase was cloned in Escherichia coli. Sequence analysis showed an open reading frame of 2136 bp, which encodes a preproenzyme of 711 amino acids. The preproenzyme is composed of a signal peptide (60 aa), a pro-peptide (259 aa), and a mature enzyme (392 aa). The mature enzyme has 49-67% amino acid sequence homology with other staphylococcal lipases.