Studies on sheep kidney nuclease. I. An improved purification method and some properties.

An improved purification method of the sheep kidney nuclease (nuclease SK) specific for single-strans nucleic acid, which includes extraction with 0.85% NaCl, treatment with DEAE-cellulose, fractionation with polyethylene glycol, phospho-cellulose chromatography, CM-Sephadex chromatography and phospho-cellulose rechromatography is described. The nuclease was purified approx. 390-fold. Identity was established by comparison with known properties. Molecular weight was estimated to be 52 000-53 000 by gel filtration on Sephadex G-100. The properties of the purified enzyme agreed well those reported previously. The purified enzyme hydrolyzed heat-denatured calf thymus DNA, yeast RNA and no hydrolytic activity for native calf thymus DNA, A2'-pA, A3'-pA, ADP, ATP, 5'-AMP and cyclic AMP.