Basic Charges on Mammalian R bonuclease Molecules and the Ability to Attack Double‐Stranded. RNA

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Abstract
A ribonuclease recently isolated from the pancreas of the lesser rorqual or pike whale (Ba1aenoptera acutorostrata), definitely more basic than bovine ribonuclease A, degrades very efficiently double‐stranded RNA under conditions where the action of bovine pancreatic ribonuclease is minimal.On the contrary, a ribonuclease from the pancreas of reindeer, definitely less basic than bovine ribonuclease A, is also, significantly less active than the bovine enzyme at degrading the doublehelical RNA.Two ribonucleases (from the pancreas of guinea pig, the A component, and red deer), with a net charge and a number of basic amino acids similar to those of bovine pancreatic ribonuclease, show an activity on double‐stranded RNA which is indistinguishable from that of bovine ribonuclease A.Finally, a ribonuclease from the pancreas of rat, having a net charge equal to that of bovine ribonuclease A, but three basic residues more than the latter enzyme, shows a modest activity towards the double‐helical RNA.These results are compatible with the idea that the action on secondary structures of RNA by ribonucleases non‐specific for double‐stranded RNA may be related to the number (and possibly the position) of basic charges on the protein molecules.