Characterization of a C-kinase inhibitory fraction

A broad area of C-kinase inhibitory activity was detected after DEAE-cellulose chromatography of 20,000 g supernatant of rat stomach homogenate. Attempts to characterize the inhibitory moiety indicated that it was a non-protein, low molecular weight substance which eluted immediately after C-kinase activity. Similar inhibition was observed in the presence of KC1, the salt used in the elution buffer. Several other salts examined also displayed inhibition of C-kinase activity. Kinetic analysis showed that both KC1 and the inhibitor displayed competitive inhibition of histones and gave identical inhibitor constants.