Inhibition of Nigerian Echis ocellatus Phospholipase A2: Perspectives and Opportunities in Venomics

The most effective and acceptable therapy for snakebite victims is the immediate administration of
antivenin following envenomation which is limited by problems of hypersensitivity reactions in
sensitive individuals and its inability to resolve the local effects of the venom. Phospholipase A2
Inhibitor from Echis ocellatus Serum (PIES) was isolated, partially purified and characterized. The
neutralizing protein from E. ocellatus serum inhibited the E. ocellatus (carpet viper) venom
phospholipase A2 (PLA2) enzyme in a dose dependent manner. A two step purification process on
sephadex G-200 column chromatography and DEAE- cellulose chromatography gave an active
fraction that inhibited the venom PLA2 by 78%. The result from SDS-PAGE showed the inhibitor to be
a 24.98kDa protein and its kinetic study revealed a mixed pattern of inhibition on the carpet viper
venom PLA2 with an estimated Ki values of 3.8%(v/v) to 7.3%(v/v). The study was carried out at the
Department of Biochemistry, Faculty of Science, Ahmadu Bello University Zaria, Nigeria from June
2011 to August 2012. The relevance of these findings towards understanding the biochemistry of
carpet viper envenomation and the development of a novel antivenin drug in future targeting the
activity of PIES are discussed.