* To whom correspondence should be addressed.
Received April 16, 2009; Revision received May 6, 2009
In this review, we have compiled the data on pharmacological activities associated with endogenous purine release related enzymes—nucleases (DNases, RNases, and phosphodiesterases). The results of studies on toxic effects of these enzymes, emphasizing the future directions in this field, are summarized. One of the major problems facing toxicologists is the identification and characterization of specific venom nucleases since they share similar substrate specificities and biochemical properties. In this review, we have attempted to clarify some of the discrepancies about these enzymes. Further, we have tried to correlate the existence of nuclease enzymes in relation to endogenous release of purines, a multitoxin, during snake envenomation, and we also discuss the possible actions of purines. We hope that this review will stimulate renewed interest among toxicologists to biologically characterize these enzymes and elucidate their role in envenomation.
KEY WORDS: purines, DNase, RNase, phosphodiesterase, snake envenomation, adenosine