Cyclic adenosine 3′:5′-monophosphate (cyclic AMP)-dependent and -independent protein kinases were detected and partially characterized in soluble extracts from mouse epidermis. Cyclic AMP-dependent histone kinase activity was separated from cyclic AMP-independent casein kinase activity by DEAE-Sephadex chromatography. The application of the tumor promoters croton oil or 12-O-tetradecanoyl-phorbol-13-acetate to mouse skin caused a rapid increase in the soluble protein extractable from the epidermis resulting in a decrease in the specific activity of both classes of protein kinase when expressed on a protein basis. No change in the activities of either the cyclic AMP-dependent or -independent enzymes was observed when expressed relative to the DNA content.


This work was supported by the Australian Research Grants Committee and the Australian Tobacco Research Foundation.

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