Nitric-oxide synthase (flavodoxin) (EC 1.14.14.47, nitric oxide synthetase, NO synthase) is an enzyme with systematic name L-arginine,reduced flavodoxin:oxygen oxidoreductase (nitric-oxide-forming). This enzyme catalyses the following chemical reaction2 L-arginine + 3 reduced flavodoxin + 3 H+ + 4 O2 2 L-citrulline + 2 nitric oxide + 3 oxidized flavodoxin + 4 H2O (overall reaction) (1a) 2 L-arginine + 2 reduced flavodoxin 2 H+ + 2 O2 2 Nω-hydroxy-L-arginine + 2 oxidized flavodoxin + 2 H2O (1b) 2 Nω-hydroxy-L-arginine + reduced flavodoxin + H+ + 2 O2 2 L-citrulline + 2 nitric oxide + oxidized flavodoxin + 2 H2O