Among the enzymes found in snake venom, ribonuclease (RNase) has been known to have the potential effect against cancer and HIV. In a previous report, the author and his colleague have demonstrated that RNase from Vietnamese black cobra (Naja naja) venom differed from all the other identified RNase for its extremely low optimal value of pH. The results in this study showed that it also differed in nonlinear activity dependence on the enzyme concentrations and a sigmoidal curve of saturation with the substrate. This enzyme expressed the maximal activity at the ionic strength of 10 mM of the reaction buffers. Ammonium sulfate entirely suppressed the enzyme activity at the concentration over 70 mM, and sodium chloride reduced the activity by 70% at the level over 100 mM. No magnesium ion was needed for the activation of this RNase.
Snake Venoms ; Snakes ; Animals, Poisonous ; Black Cobra Venom