A study of the ribonuclease activity of snake venoms.

The observation that snake venoms are able to hydrolyze thymus and yeast nucleic acids was first made by Delezenne and Morel (1) in 1919. This discovery remained practically forgotten until 1945 when Gulland and Walsh (2) employed the nuclease in the venom of Vipera russelli in studying the composition of yeast ribonucleic acid. The presence of nucleases in snake venoms assumes a r61e of great importance if their property can be correlated with the mechanism of poisoning by the venoms, as well as with other physiological actions of snake venoms, particularly the action upon cancer cells (3-5). The connection between cytoplasmic ribonucleic acid (RNA) and protein synthesis in the cell, as emphasized by Caspersson and others (668), is highly suggestive of the relation between nucleic acids and the physiological processes involving normal and atypical growth. Because of the lack of specific knowledge concerning the nuclease activity of snake venoms and because of the possible importance of these enzymes in relation to some of their physiological actions, the present study has been undertaken. In this investigation ribonuclease activities of various snake venoms have been determined, and a detailed study of the properties of one venom in particular, Bothrops jararaca, has been carried out. In the latter case the effects of various inhibitors and activators, some of which are known to influence the toxicity of the venom, have been studied in an attempt to observe whether any correlation between toxicity and ribonuclease activity exists.