Figure 1From: Emergent role of gasotransmitters in ischemia-reperfusion injuryEnzymatic Synthesis of Nitric Oxide. Nitric oxide (NO) is produced from amino acid L-arginine by the enzymatic action of nitric oxide synthase (NOS). There are there forms of NOS: endothelial NOS (eNOS), neuronal NOS (nNOS), and inducible NOS (iNOS). NO activates guanylate cyclase (GC), which leads to increased production of 3',5'-monophosphate (cGMP).Back to article page