Nucleic acid-protein interactions. Degradation of double-stranded RNA by glycosylated ribonucleases

1. Extensively glycosylated ribonucleases, like the enzymes from pig and horse pancreas, show a much higher activity on double-stranded RNAs than similarly charged, carbohydrate-free RNAases under stranded assay conditions (relatively high salt concentrations). Glycosylated pig and horse pancreas RNAases also show a larger destabilizing effect on double-stranded poly[d(A-T)] X poly[d(A-T)], than that displayed by bovine RNAase A under these conditions. Both activities show a similar dependence on the ionic strength of the medium. 2. A partial enzymic removal of the heterosaccharide side chains from pig and horse RNAases reduces but their degradative activity on double-stranded RNA and their destabilizing action on poly[d(A-T)] X poly[d(A-T)]. 3. These results are tentatively correlated with a modification of the microenvironment of the enzyme protein caused by its extensive glycosylation.