RNA degrading activity is tightly associated with the multicatalytic proteinase, ingensin

Abstract
The multicatalytic proteinase, ingensin, was purified to homogeneity from chicken liver. rRNA‐degrading activity was co‐eluted with the purified multicatalytic proteinase from a TSK‐3000SW column. This RNA‐degrading activity was inactivated by heat treatment and the addition of a low concentration of SDS. Therefore, the RNA‐degrading activity co‐eluted with the multicatalytic proteinase was not due to contamination by low‐molecular‐mass RNases. These results strongly suggest that this RNA‐degrading activity was tightly associated with the multicatalytic proteinase, ingensin.