An enzyme complex, composed of regulatory and catalytic subunits, that catalyzes protein phosphorylation. Inactive forms of the enzyme have two regulatory chains and two catalytic chains; activation by cAMP produces two active catalytic monomers and a regulatory dimer. [ https://www.worldcat.org/search?q=bn%3A0198506732 https://enzyme.expasy.org/EC/2.7.11.11 ]