| Abstract: | An novel acid ribonuclease has been purified approx. 1300 fold from acid extract of developing white-spotted charr (Salvelinus leucomaenis) testes. The final preparation of the enzyme was homogeneous on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS). The molecular weight was determined to be 20,000 with both Sephadex gel filtration and SDS-polyacrylamide gel electrophoresis. The isoelectric point was determined to be 6.4 and the hydrolytic activity was stimulated with low concentration of phosphate. The enzyme has an optimal pH at 5.5 and hydrolyzed yeast RNA and several synthetic homopolyribonucleotides. Under appropriate conditions, the enzyme hydrolyzed substrates, yeast RNA, poly (I), poly (A) and poly (U), in a ratio of 100:900:30:20, respectively. However, poly (C) could not be hydrolyzed under any conditions tested so far. Yeast RNA was hydrolyzed into monoto pentanucleotides. The range of substrate-specificity of this enzyme will be discussed on the basis of the analysis of these products. |
