Preliminary studies on ribonucleases from Poa pratensis seeds

Abstract

Ribonuclease was extracted from Poa pratensis seeds with 0.1 M acetate buffer, pH 5.1, and then precipitated with alcohol. The enzyme was separated into 5 fractions (I-V) after chromatography on DEAE-cellulose at pH 5.1. The enzymes were stable at 50°C, at pH 7.1. The activity of ribonucleases I, II, III and V were optimal at pH 7.1-7.3, and that of ribonuclease IV at pH 8.1. Ali enzymes were inhibited by Ca²⁺ and EDTA. Mg²⁺ inhibited the activity of ribonucleases II, III, IV, and had no influence on that of ribonucleases I and V. Ribonucleases IV and V showed only one activity band in disc electrophoresis, whereas ribonucleases, I, II and III were found to be heterogenous.