The results of studies on ribonuclease from king cobra venom (Ophiophagus hannah)

Abstract

In this paper Ribonuclease (RNase) from Vietnam king cobra (Ophiophagus hannah) venom was characterized in detail by ion-exchange chromatographic methods and its some properties were studied. It seems that king cobra venom RNase is very thermostable: treatment by heating enzyme solutions (in a water bath) for 5 min at temperature from 70^oC to 100^oC almost does not abolish its activity. The existence of this enzyme in multiple molecular forms was confirmed by chromatographic methods, including ion-exchange chromatography on columns with CM-cellulose and SP Sepharose 4 Fast Flow and gel-filtration on columns with Superdex 200 and Superdex 75. These methods have revealed at least 4 molecular forms of this enzyme differing in net charge and 4 forms differing in molecular size. The enzyme is the most active in the pH range of 1.5 - 4.0 and its pH optimum is about 2.00 ± 0.25 in glycine or in mix glycine-citrate (in a ratio 1: 1) buffers. These properties of RNase from Vietnam king cobra venom is very similar to those ones of the enzyme from Vietnam cobra venom.