Ribonuclease from cobra snake venom: purification by affinity chromatography and further characterization.

A ribonuclease from cobra snake venom was isolated and purified to homogeneity using antibody-affinity chromatography, increasing the yield fourfold. The purified enzyme showed cytidylic acid specificity, as reported earlier. Further, the effects of temperature, pH, metal ions, inhibitors, and urea on the enzyme activity were studied. Snake venom RNase exhibited salt-dependent reversible association-dissociation behaviour. Immunological studies indicate that this enzyme shares one of the antigenic sites of RNase A. The partial N-terminal sequence of the enzyme showed considerable homology with phospholipases from snake venom; however, the enzyme itself did not show any phospholipase activity.