Answer to Pharmacology MCQ 452

• Formed from ATP by an enzyme called adenylyl cyclase
• Anchored to membrane with catalytic portion in the cytosol
• Normally inactive, becomes active when bound to G alpha (can also be inactivated by a G protein)
• CAMP levels rise rapidly
• Enzyme is only active for a short period of time (until GTP is converted to GDP)
• Levels are only high for a short time as well
• Enzyme called phosphodiesterase degrades CAMP
• cAMP effects
• main intracellular target is PKA = protein Kinase A
• phosphorylates wide variety of proteins by transferring a phosphate from ATP to a serine or threonine residue on target protein
• function varies from cell to cell

Category: Pharmacology MCQs