cGMP (or 3'-5'-cyclic GMP
?) is a
second messenger molecule, used for
intracellular signal transduction. It is made from GTP
? by [guanylate cyclase]
?. Its main purpose is the regulation of
protein kinases; it is also use to regulate the passage of cation
?s (for example,
Ca2+)through
ion channels, a mechanism used in retina
? cells by
mammals.