part of Oxidation/Reduction Arginine and proline metabolism 3 NADPH + 2 L-Arginine + 4 O2 + 3 H+ = 3 NADP+ + 2 L-Citrulline + 2 Nitric oxide + 4 H2O( EC:1.14.13.39 ) EC:1.14.13.39 IEV:0003214 IMR:0100128 IMR:0200019 IMR:0200030 IMR:0200067 IMR:0200217 IMR:0200357 IMR:0200428 IMR:0200463 KEGG:R00557 KEGG:map00330 NADPH + L-Arginine + O2 = NADP+ + L-Citrulline + NO( EC:1.14.13.39 ):multi-step reaction event