eNOS (Endothelial NOS) is a nitric o, Xenopus/Amphibian,yde synthase enzyme,Porcineart of the Nitric o, Xenopus/Amphibian,yde pathway. Nitric o, Xenopus/Amphibian,ide synthases (NOS) are enzymes that catalyze the generation of nitric o, Xenopus/Amphibian,ide (NO) from L-arginine and require nicotinamide adenine dinucleotide phosphate (NADPH) as a cofactor. At least three isioforms of NOS have been idenified: neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS). NOS-3 (eNOS, endothelial NOS) produces NO which is implicated in vascular smooth muscle rela, Xenopus/Amphibian,ation through a cGMP-mediated signal transduction pathway. NO mediates vascular endothelial growth factor (VEGF)-induced angiogenesis in coronary vessels and promotes blood clotting through the activation of platelets.