NOguanylaatsüklasecGMP

NOguanylyl cyclase cGMP refers to a class of enzymes responsible for catalyzing the synthesis of cyclic guanosine monophosphate (cGMP). This enzyme plays a critical role in various cellular signaling pathways. There are two main isoforms of this enzyme: a soluble form (sGC) and a particulate membrane-bound form (mGC).

The soluble guanylyl cyclase (sGC) is activated by nitric oxide (NO). When NO binds to the heme prosthetic group of sGC, it induces a conformational change that increases its catalytic activity. This leads to a rapid increase in intracellular cGMP levels. The particulate guanylyl cyclase (mGC) is activated by natriuretic peptides, such as atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), which bind to their respective receptors on the cell surface. This receptor activation then triggers the enzymatic activity of the associated mGC.

cGMP acts as a second messenger, mediating a wide range of physiological processes. These include vasodilation, smooth muscle relaxation, neurotransmission, and platelet aggregation. The signaling cascade initiated by cGMP often involves the activation or inhibition of protein kinases, such as protein kinase G (PKG), which then phosphorylates various target proteins, altering their function. Dysregulation of NO-sGC-cGMP signaling has been implicated in various diseases, including cardiovascular disorders and neurological conditions.