Partial Purification and Characterization of Phospholipase A2 Inhibitor from Echis ocellatus Serum

Abstract

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.