Purification and Properties of Ribonuclease from Yeast*

Abstract

The enzyme was purified by autolysis (37[degree]C, 3 hours., pH 9) in the presence of 5% ammonium sulfate, chromatography on a carboxymethyl-cellulose column equlibrated with 0.01 M ammonium acetate, and rechromatography of the active effluents. The preparation possessed RNAase purified about 230-fold and catalyzed hydrolysis of yeast RNA to yield acid-soluble products which were identified as various 3-mononucleotides, but the enzyme could not split DNA, or 2, 3-cyclic nucleotide. The enzyme was markedly activated by 0.1 M phosphate, and completely inhibited by 10-4 M Zn2++; the inhibition could be reversed by the addition of EDTA, citrate, or histidine.