ID 1.14.13.250 DE nitrosourea synthase. CA H(+) + N(omega)-methyl-L-arginine + 2 NADH + 3 O2 = 3 H2O + N(delta)- CA hydroxy-N(omega)-methyl-N(omega)-nitroso-L-citrulline + 2 NAD(+). CC -!- The enzyme, characterized from the bacterium Streptomyces CC achromogenes subsp. streptozoticus, catalyzes a complex multi-step CC reaction during the biosynthesis of the glucosamine-nitrosourea CC antibiotic streptozotocin. CC -!- The overall reaction is an oxidative rearrangement of the guanidine CC group of N(omega)-methyl-L-arginine, generating an N-nitrosourea CC product. CC -!- The enzyme hydroxylates its substrate at the N(delta) position, CC followed by a second hydroxylation at the N(omega)' position. It then CC catalyzes an oxidative rearrangement to form N(delta)-hydroxy- CC N(omega)-methyl-N(omega)-nitroso-L-citrulline. CC -!- This product is unstable, and degrades non-enzymically into nitric CC oxide and the denitrosated product N(delta)-hydroxy-N(omega)-methyl- CC L-citrulline. CC -!- The enzyme contains two active sites, each of which utilizes a CC different iron-containing cofactor. DR A0A411MR89, SZNF_STRC2 ; //