Results of the ribonuclease isolation from the cobra venom by ion-exchange column with CM-cellulose method

Abstract

In this paper, the cobra (Naja atra Cantor, 1842) venom ribonuclease (RNase) was isolated of ion-exchange column with CM-cellulose method. The chromatographic isolation was carried out at different values of pH within an interval of pH = 4.4 – 5.8. At pH > 5.0, the cobra venom RNase was almost always eluded from the column in two picks at salt concentrations of about 0.6 M and 0.8 M NaCl; but in some cases - in three picks at salt concentrations of about 0.5 M, 0.65 M and 0.86 M NaCl, respectively; whereas, at pH < 5.0, the cobra venom RNase was always eluded from the column in single broad pick. The forms of the cobra venom RNase corresponding to these picks were designated as SK-1, SK-2 and SK-3, respectively. It seemed that these RNase forms were differed from each other in many properties, such as an optimum of pH (pH_opt) and the kinetic property. Thus, the pH_opt of the form SK-2 was about 2.5, whereas this value of the forms SK-1 and SK-3 was the same and about 2.0. Besides, two main forms SK-2 and SK-3 had sigmoidal curves of the saturation of the enzyme with the substrate, but they differed significantly in an affinity to the substrate.