Separation of regulatory and catalytic subunits of the cyclic 3',5'-adenosine monophosphate-dependent protein kinase(s) of rabbit skeletal muscle

The cyclic 3′, 5′-adenosine monophosphate-dependent (cAMP-dependent) protein kinase(s) from rabbit skeletal muscle has been separated into catalytic and regulatory subunits by affinity chromatography utilizing a casein-Sepharose column in the presence of cAMP. The isolated catalytic subunit manifests full activity in the absence of cAMP but its requirement for this nucleotide is regained when the enzyme is reconstituted by addition of the regulatory subunit. Evidence is presented for the existence of more than a single type of regulatory or cAMP-binding subunit in muscle.