Abstract
A novel non-toxic phospholipase A(2) was purified to homogeneity in a single chromatography step from the venom of Walterinnesia aegyptia, a monotypic elapid snake caught in Saudi Arabia, and its antimicrobial and hemolytic properties were evaluated as well. This enzyme, namely WaPLA(2), is a homodimer with an estimated molecular mass of 30 kDa, and its NH2-terminal sequence exhibits a significant degree of similarity with PLA(2) group-I. At optimal pH (8.5) and temperature (45 degrees C), the purified PLA(2) exhibited a specific activity of 2100 U/mg, and it requires bile salts and Ca2+ for its activity. However, other cations such as Cd2+ and Hg2+ diminished the enzyme activity remarkably, thereby suggesting that the catalytic site arrangement has an exclusive structure for Ca2+ binding. Furthermore, WaPLA(2) maintained almost 100% and 60% of its full activity in a pH range of 6.0-10 after 24 h incubation or after 60 min treatment at 70 degrees C, respectively. In the biological activity assays, WaPLA(2) displayed potent indirectly hemolytic and antimicrobial activities that were strongly correlated. These promising findings encourage further in-depth research to understand the molecular mechanism of WaPLA(2)'s antimicrobial properties for its possible use as a potential therapeutic lead molecule for treating infections. (C) 2018 Elsevier B.V. All rights reserved.