Nitric oxide synthase (NAD(P)H dependent)

Nitric-oxide synthase (NAD(P)H-dependent) (EC 1.14.13.165, nitric oxide synthetase, NO synthase) is an enzyme with systematic name L-arginine,NAD(P)H:oxygen oxidoreductase (nitric-oxide-forming). This enzyme catalyses the following chemical reaction

2 L-arginine + 3 NAD(P)H + 3 H⁺ + 4 O₂ ⇌ 2 L-citrulline + 2 nitric oxide + 3 NAD(P)+ + 4 H₂O (overall reaction) (1a) 2 L-arginine + 2 NAD(P)H + 2 H⁺ + 2 O₂ ⇌ 2 Nomega-hydroxy-L-arginine + 2 NAD(P)⁺ + 2 H₂O (1b) 2 Nomega-hydroxy-L-arginine + NAD(P)H + H⁺ + 2 O₂ ⇌ 2 L-citrulline + 2 nitric oxide + NAD(P)⁺ + 2 H₂O

Nitric-oxide synthase (NAD(P)H-dependent) binds heme (iron protoporphyrin IX) and tetrahydrobiopterin.