[HTML][HTML] Oxygen reduction by nitric-oxide synthases
Nitric-oxide synthases (NOS, 1 EC 1.14. 13.39) are hemeproteins that catalyze oxidation of L-
arginine to NO and L-citrulline. Three main isozymes exist in mammals that are regulated by
distinct genes (1–6): a constitutive neuronal NOS (nNOS or NOS I),(7, 8), an endotoxin-and
cytokine-inducible NOS (iNOS or NOS II)(9, 10), and a constitutive endothelial NOS (eNOS
or NOS III)(11). Although NOS have some unique features that distinguish them from other
hemeprotein monooxygenases such as cytochrome P-450s, there are, nevertheless, a …
arginine to NO and L-citrulline. Three main isozymes exist in mammals that are regulated by
distinct genes (1–6): a constitutive neuronal NOS (nNOS or NOS I),(7, 8), an endotoxin-and
cytokine-inducible NOS (iNOS or NOS II)(9, 10), and a constitutive endothelial NOS (eNOS
or NOS III)(11). Although NOS have some unique features that distinguish them from other
hemeprotein monooxygenases such as cytochrome P-450s, there are, nevertheless, a …