In the study, using the kinetic method for the examination of the dependence between the specific activity of the enzyme and the concentration of the enzyme itself in the combined reaction, the researchers have proved that the Ribonuclease (R.Nase) molecule of the black cobra (Naja naja) venom exits at least in two interconvertible forms with the difference in specific activity of almost one grade. These two forms are probably the different oligomers or configurations, temporarily named as the kinetic forms of R.Nase found in the black cobra venom.
Snake Venoms ; Ribonucleases ; Polymorphism, Genetic

By ion-exchange chromatography, the existance of Ribonuclease from Vietnam’s black cobra. Venum in multiple molecular forms was confirmed. Its two separated peaks were noted on CM-cellulose column chromatography. At present , the nature of these RNase chromatographic forms are unknown, but it is probably that they possess quaternary structure
Ribonucleases ; Venoms ; Snakes

Evaluate the influences of some factors as enzyme level, the time of diluting enzyme solution, substrate level and temperature on pH value of RNase from Vietnam Cobra (Naja naja) venom. Results: the changes of pH value for cobra venom RNase can be depended on concentrations of the enzyme and substrate. This variation in the pH value of the enzyme can be explained by existence of this RNase as an enzyme system composed of some interconvertible forms. The interconversion between these enzyme forms is very slow process (counting by hours) in comparison with the rate of reactions
Cobra ; Hydrogen-Ion Concentration ; Ribonucleases

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