ニジマス幽門垂から分離したアルカリ性RNaseについて
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概要
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The alkaline RNA-depolymerase in the pyloric caeca of rainbow trout was purified about 160 fold in order to study the properties of this enzyme. The purified enzyme was free from the phosphomonoesterases and the phosphodiesterase while only a little alkaline DNase activity was observed. The optimum pH for the enzyme activity was approximately 8.5 in the Tris-HCl buffer. The enzyme was inactivated irreversibly under Ca++ free conditions. Mg++, Ba++, K+ and Na+ did not show any effects on the enzyme activity at 4mM concentration, whereas Co++, Cd++ and Hg++ inhibited remarkably at the same concentration. The enzyme digested RNA completely to the acid soluble fraction. In the digestion products of the RNA, four kinds of mononucleotides, i.e. CMP, UMP, AMP and GMP, were found. In the digestion test using homopolynucleotide as the substrate, the enzyme hydrolyzed the polynucleotide forming the 2:3 cyclic nucleotide. It was confirmed from these specificities that, among the various RNA-depolymerases, this enzyme can be classified as an RNase (EC. 2.7.7.17).