Abstract

Phospholipase A₂ (EC. 3.1.1.4) was isolated and partially characterized from the venom of Echis ocellatus. The enzyme was purified 13.5-fold with a yield of 86.69% on DEAE-Sephadex G-75 column. The PLA₂ from E. ocellatus venom had broad pH and temperature ranges with optima of 7.5 and 40^oC respectively.  Initial velocity studies for the determination of kinetic constants with L-α- lecithin as substrate revealed a Km and Vmax of 1mg/ml and 0.35 mmoles/min respectively. The enzyme activity was enhanced by Ca²⁺ and strongly inhibited by Mg²⁺ and Co²⁺. Cu²⁺ was fairly inhibitory to the enzyme. The relevance of these findings towards understanding the biochemistry of E. ocellatus envenomation and development of antivenom for E. ocellatus venom is discussed.

Key words: Echis ocellatus, PLA₂, venom.