cGMP-specific 3',5'-cyclic phosphodiesterase (PDE5) (PDE5)

cGMP-specific 3',5'-cyclic phosphodiesterases are a class of enzymes, primarily represented by PDE5, PDE6, and PDE9, that regulate the levels of the secondary messenger cyclic guanosine monophosphate (cGMP) by catalyzing its conversion to 5'-GMP (UniProt: O76074). These enzymes are pivotal in various physiological processes, including smooth muscle relaxation, vasodilation, and visual phototransduction (StatPearls: NBK549843). PDE5 is the most clinically significant member, found predominantly in the corpus cavernosum and pulmonary vasculature, making it a primary target for treating erectile dysfunction and pulmonary arterial hypertension (PubMed: 15082086). PDE6 is localized in the retina and is essential for converting light signals into electrical impulses, while PDE9 is involved in metabolic and cognitive functions (NIH: Gene 5145). Therapeutic agents such as sildenafil and tadalafil work by inhibiting these enzymes to prolong the vasodilatory effects of nitric oxide (Wikipedia: PDE5 inhibitor). However, cross-reactivity with other PDE isoforms can lead to side effects like visual disturbances or hypotension, particularly when used alongside nitrate-based medications (StatPearls: NBK549843).

Other names

Phosphodiesterase 5PDE5AcGMP-binding cGMP-specific phosphodiesterasePDE6PDE9

Competitive inhibition of the catalytic site of the enzyme, preventing the hydrolysis of cyclic guanosine monophosphate (cGMP) to 5'-GMP, thereby increasing intracellular cGMP concentrations and enhancing nitric oxide-mediated signaling (StatPearls: NBK549843).