Biochemical, Kinetic and Biological Properties of Group V Phospholipase A2 from Dromedary

Secretory group V phospholipase A2 (PLA(2)-V) is known to be involved in inflammatory processes in cellular studies, nevertheless, the biochemical and the enzymatic characteristics of this important enzyme have been unclear yet. We reported, as a first step towards understanding the biochemical properties, catalytic characteristics, antimicrobial and cytotoxic effects of this PLA(2), the production of PLA(2)-V from dromedary. The obtained DrPLA(2)-V has an absolute requirement for Ca(2+) and NaTDC for enzymatic activity with an optimum pH of 9 and temperature of 45 °C with phosphatidylethanolamine as a substrate. Kinetic parameters showed that K(cat)/Km(app) is 2.6 ± 0.02 mM(−1) s(−1). The enzyme was found to display potent Gram-positive bactericidal activity (with IC50 values of about 5 µg/mL) and antifungal activity (with IC50 values of about 25 µg/mL)in vitro. However, the purified enzyme did not display a cytotoxic effect against cancer cells.