AP BIOLOGY

Detailed explanation-1: -Adenylyl cyclases catalyze synthesis of cAMP from ATP whereas phosphodiesterases (PDEs) catalyze hydrolysis of cAMP to 5′ AMP.

Detailed explanation-2: -Once formed, cAMP can activate protein kinase A (PKA) that in turn phosphorylates intracellular proteins to mediate specific cellular responses. After its formation, cAMP is degraded to AMP by phosphodiesterases.

Detailed explanation-3: -cAMP phosphodiesterase converts cAMP into AMP by breaking the phosphodiester bond, in turn reducing the cAMP levels. Gi protein, which is a G protein that inhibits adenylyl cyclase, reducing cAMP levels.

Detailed explanation-4: -After its formation, cAMP is degraded to AMP by phosphodiesterases. The activity of AC is regulated by GPCRs through the two heterotrimeric GTP-binding protein complexes Gs and Gi.

Detailed explanation-5: -Cyclic AMP (cAMP) phosphodiesterase-4 (PDE4) enzymes degrade cAMP and underpin the compartmentalization of cAMP signaling through their targeting to particular protein complexes and intracellular locales.