An overview on nucleases (DNase, RNase, and phosphodiesterase) in snake venoms

Abstract

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.

Phosphodiesterase from Daboia russelli russelli venom: Purification, partial characterization and inhibition of platelet aggregation

“…This is due to heterogeneity of the chromatographic fraction used therein (Suwansrinon et al, 2007). PDE from snake venoms are mostly composed of single polypeptide chain (Dhananjaya and D'Souza, 2010). Exceptions do exist where PDEs are homodimers or homooligomers with disulfide linkage between the subunits, e.g., PDE from Crotalus ruber ruber is a homodimer joined by disulfide bonds (Mori et al, 1987).…”

“…Metal chelators like EDTA, 1,10-phenanthroline and citrate completely inhibit DR-PDE. Zn 2þ is usually critical for the catalytic activity of PDEs (Dhananjaya and D'Souza, 2010). Besides Zn 2þ , several transition metal ions can also activate PDEs from other sources; e.g., cAMP PDE from Mycobacteria contains Fe 2þ and Mn 2þ which are crucial for its activity (Podobnik et al, 2009).…”

“…Snake venom PDEs exhibit exonuclease activity (Dhananjaya and D'Souza, 2010). Hydrolysis of CT-DNA by DR-PDE was followed for 100 min.…”

“…For this reason, they are used in the elucidation of structure and sequence of DNAs (Ho and Gilham, 1973;Santoro et al, 2009). PDEs are ubiquitously distributed in snake venoms (Dhananjaya and D'Souza, 2010). These enzymes have high abundance in the venoms of Crotalidae and Viperidae families (Tan and Ponnudurai, 1990a,b) and low abundance in the venoms of Elapidae and Hydrophidae families Ponnudurai, 1990c, 1991).…”

Probing the Key Binding Sequence and Improvement of the Stability of a β‐Bungarotoxin‐binding Aptamer in Snake Venom

“…21 Various enzymes in snake venom, including DNases, RNases, and phosphodiesterases, have endo-or exonuclease activities that can hydrolyze nucleic acids and their derivatives. 22,23 Our previous work has shown that the original aptamer βB-1 was completely degraded by the venom of Naja naja atra. 20 Hence, improving the stability of the aptamer βB-1 in snake venom is important for its diagnostic or therapeutic uses.…”