What Is Nitric Oxide Synthase?

Nitric oxide synthase (NOS) is an isoenzyme that exists in endothelial cells, macrophages, neurophagocytic cells and nerve cells, respectively. Nitric oxide synthase is present in neurons and is selectively distributed in different brain regions. Because nitric oxide is very unstable, it seems easier to study the enzyme that produces nitric oxide, especially the discovery of nitric oxide synthase antagonists, which has greatly promoted some studies on the function of nitric oxide.

Nitric oxide synthase

nNOS (NOS1) and eNOS (NOS3) are calcium-dependent and iNOS (NOS2) is calcium-independent. nNOS is also present in myocardial tissue

NOS uses L-arginine as a substrate and uses oxygen to generate NO and L-citrulline. NOS can also generate

Nitric oxide synthase catalyzes the following reactions:

L-arginine + 3/2 NADPH + H + 2 O _{2 =} citrulline + nitric oxide + 3/2 NADP