Adenosine 3′,5′-Monophosphate (cAMP)-Binding Proteins and cAMP-Dependent Protein Kinases in Bovine Adrenal Cortical Cell Plasma Membrane*

Abstract
A cAMP-binding protein and cAMP-dependent protein kinase have been identified and partially characterized in bovine adrenocortical plasma membranes. [3H]cAMP binding to the plasma membrane preparation demonstrates both high (Kª = 4.2 × 109 M-1) and low (Kª = 1.3 × 108 M-1) affinity binding sites. cAMP-dependent protein kinase was demonstrated using both bovine histone and endogenous substrates. The detergentdependent solubilization characteristics of this cAMP-dependent protein kinase indicate that it is an integral membrane protein.