On the efficacy of commonly used ribonuclease inhibitors.

The ability of a number of commonly used inhibitors to inhibit pancreatic ribonuclease has been studied. At ribonuclease concentrations of 10 or 100 g/ml, heparin, polyvinylsulfate and proteinase K, at concentrations reported for their use in the literature, were ineffective in inhibiting RNase digestion of 3H-uridine labelled RNA from Streptomyces antibioticus. In contrast, macaloid, diethylpyrocarbonate and sodium dodecyl sulfate were all effective inhibitors, with the degree of effectiveness decreasing in the order stated. Further, at inhibitor concentrations which allowed RNase conversion of only 50% of the labelled RNA to acid soluble products, a larger percentage of the acid insoluble di estion products sedimented in the "high molecular weight" range 9 4-16s) when macaloid was the inhibitor used than when diethylpyrocarbonate was the inhibitor.