The ribonucleases of bovine skeletal muscle

Publisher Website
Google Scholar
Abstract
Bovine skeletal muscle contains small amounts of at least 6 heat- and acid-stable RNA-degrading enzymes. These results are the 1st evidence for multiple RNase in skeletal muscle. Of these, 3 were highly purified, and each was a pyrimidine-specific endoRNase by use of a rapid sequencing technique employing gel electrophoresis. Synthetic co-polymers containing adenylate or guanylate residues, in addition to pyrimidine residues, are hydrolyzed at higher rates than are the pyrimidine homopolymers. With 0.63 mM yeast RNA as substrate, all 3 enzymes (RNases I, II and III) are optimally active in alkaline solution (pH 7.5-8.5) containing 0.05-0.15 M univalent salts, do not require bivalent cations and have MW of 13,000-20,000. The properties of muscle RNase I are very similar to those of bovine pancreatic RNase A. Muscle RNases II and III have characteristics similar to those of RNases found in various other bovine tissues. In common with all previously studied pyrimidine-specific endoRNases, the bovine muscle RNases are inhibited by such purine homopolynucleotides as polyadenylate. Polyamines, present in low concentrations, can reverse or regulate the amount of inhibition of enzyme activity.