Study of autophosphorylation of isoenzymes of cyclic AMP-dependent protein kinases.

Type I and type II cyclic AMP-dependent protein kinases, present in the cytosol from each of five rat and two bovine tissues, were separated from one another by DEAE-cellulose column chromatography in order to study their possible autophosphorylation. In each of the tissues studied, autophosphorylation of the regulatory subunit of the cyclic AMP-dependent protein kinase by the catalytic subunit could be demonstrated with the type II enzyme but not with the type I enzyme.