The pharmacological role of nucleotidases in snake venoms.

Several hydrolytic enzymes of snake venom have evolved to interfere in various physiological processes, which are well defined. However, hydrolytic enzymes such as nucleotidases (5'nucleotidase, ATPase, and ADPase) are less studied and their pharmacological role in venoms is not clearly defined. Very few studies have shown the pharmacological importance of these endogenous purine release related enzymes in venoms. The near-ubiquitous distribution of these enzymes in venoms, suggests a significant role for these enzymes in envenomation. It is suggested that their major function is in the generation of purines (mainly adenosine)-a multitoxin. Therefore, it appears that these enzymes play a central role in liberating adenosine and through the action of adenosine help in prey immobilization. However, apart from this, these enzymes could also possess other pharmacological activities. Further research is needed to biologically characterize these enzymes in snake venoms, such that their role in venom is clearly established.