Guanylate cyclase

Guanylate cyclase (, also known as guanylyl cyclase or GC) is a lyase enzyme.

Reaction
It catalyzes the conversion of guanosine triphosphate (GTP) to 3',5'-cyclic guanosine monophosphate (cGMP) and pyrophosphate:

Types
There are soluble and membrane-bound forms of guanylyl cyclases.
 * Soluble GC (sGC) is activated by nitric oxide, most notably involved in vasodilation.
 * Membrane-bound forms are enzyme-linked receptors:
 * GC-A & GC-B for natriuretic factors such as atrial natriuretic factor (ANF)
 * GC-C for guanylin and uroguanylin. (See also guanylyl cyclase c)

Function
Once formed, cGMP can be degraded by phosphodiesterases, which themselves are under different forms of regulation, depending on the tissue.

Like cAMP, cGMP is known to regulate many cellular proteins, such as protein kinases, ion channels, and phosphodiesterases.