The relationship of certain enzymes in cobra and rattlesnake venoms to the mechanism of action of these venoms

Abstract

Naja flava (cobra) venom was separated into 2 electrophoretically distinct fractions, one (fraction 1) 4 times as toxic as the other (fraction 2). Fraction 1 is composed of 2 highly mobile, strongly basic proteins comprising 80% by weight of the venom; fraction 2, which makes up the remaining 20% of the venom, consists of 3 proteins of low mobility. This fraction gives a positive Molisch test for carbohydrate. Fraction 1 is much less potent than fraction 2 with respect to lecithinase A, adenosine triphosphatase, diphosphopyridine nucleotidase and ribonuclease activities, indicating that none of these enzyme activities is of prime importance toxicologically. Fraction 2 is also a much more potent inhibitor of succinic dehydrogenase than fraction 1. Thus although the lecithinase A activity may well be responsible for the inhibition of succinic dehydrogenase, neither action is of importance as a toxic mechanism. Comparison of the adenosine triphosphatase, diphosphopyridine nucleotidase and ribonuclease activities of Naja flava venom with those of 2 Crotalus venomas (C. t. terrificus and C. adamanteus) revealed that Naja flava venom was less active in each case.