Phosphodiesterase Flashcards
A hydrolase that breaks a phosphodiester bond
Phosphodiesterase
How are phosphodiester bonds formed?
Two hydroxyl groups of phosphoric acid react with two hydroxyl groups attached to carbons to form ester bonds
Formed when adenylyl cyclase catalyzes the conversion of ATP to cAMP
Formed when guanylyl cyclase catalyzes the conversion of GTP to cGMP
Phosphodiesterase physiologic function
Sole known enzyme for terminating cyclic nucleotide signals- regulating physical and pathologic processes
Phosphodiesterase that is nonselective for cAMP and cGMP, but has10x affinity for cAMP
PDE 3
Phosphodiesterase that is found in the heart, vascular and placental smooth muscle, and tissues important to homeostasis (liver, pancreatic B-cells, adipocytes)
PDE3
Phosphodiesterase that is inhibited by milrinone and amrinone
PDE3
Effect of PDE3 inhibition on cardiac myocytes
Increased cAMP = positive chronotropy, dromotropy, inotropy, and lusitropy
Effect of PDE3 inhibition on vascular smooth muscle
Increased cAMP = vasodilation
Phosphodiesterase inhibitors that are called an inodilator
PDE3 inhibitors
Phosphodiesterase that is cGMP selective
PDE5
Phosphodiesterase that is found at high levels in the corpus cavernosus, vascular smooth muscle, and platelets
PDE5
Phosphodiesterase inhibitors that are metabolized by CYP450 in the liver
PDE 5 inhibitors
Phosphodiesterase inhibitors that end in -afil
PDE 5 inhibitors
Phosphodiesterase that is cAMP selective and found throughout the body
PDE4
Phosphodiesterase that modulates B2-adrenergic responses in pulmonary smooth muscle
PDE4
