Ribonuclease activiy associated with chick embryo chorioallantoic plasma membranes

Abstract

Ribonuclease activiy was found associated with plasma membranes isolated from chick embryo chorioallantoic cells. The enzyme was solubilized with buffered 1% Triton X-100 and purified 40-fold by 1-butanol extraction and gel-filtration on Sephadex G-100. The purified Rnase was found to be free of deoxyribonuclease, alkaline phosphatase and decyclizing 2',3'-phosphodiesterase activities. the enzyme is capable to degrade RNA and polycytidylic acid into acid-soluble oligonucleotides terminated in 3'-phosphate. No nucleoside monophosphates and 2',3'-cyclic nucleoside monophosphates were detected. The optimal pH of RNA and poly C hydrolysis were 7.2 and 7.8, the optimal temperatures 60 and 45°C, respectively. The purified enzyme is thermolabile, and it requires monovalent cations for the full enzyme activity.