Introduction
PKA or Protein Kinase A is an enzyme that phosophorylate proteins in presence of cAMP.
Mechanism of action
PKA holoenzyme contains 2 catalytic and 2 regulatory subunits. Regulatory subunits prevents catalytic subunits phosphorylate target proteins. Upon binding of 4 cAMP to these 2 regulatory subunits these subunits dissociate from catalytic subunits and thus activate them.
Many intracellular signaling pathways take advantage of PKA as an enzyme to relay signals.