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EC 1.14.13.39 Details
show Brenda entryEC number
1.14.13.39
Accepted name
nitric-oxide synthase (NADPH)
Reaction
2 L-arginine + 3 NADPH + 3 H+ + 4 O2 = 2 L-citrulline + 2 nitric oxide + 3 NADP+ + 4 H2O (overall reaction);;(1a) 2 L-arginine + 2 NADPH + 2 H+ + 2 O2 = 2 Nω-hydroxy-L-arginine + 2 NADP+ + 2 H2O ;;(1b) 2 Nω-hydroxy-L-arginine + NADPH + H+ + 2 O2 = 2 L-citrulline + 2 nitric oxide + NADP+ + 2 H2O
Other name(s)
NOS (gene name),
nitric oxide synthetase (ambiguous),
endothelium-derived relaxation factor-forming enzyme,
endothelium-derived relaxing factor synthase,
NO synthase (ambiguous),
NADPH-diaphorase (ambiguous)
Systematic name
L-arginine,NADPH:oxygen oxidoreductase (nitric-oxide-forming)
CAS registry number
125978-95-2
Comment
The enzyme consists of linked oxygenase and reductase domains. The eukaryotic enzyme binds FAD, FMN, heme (iron protoporphyrin IX) and tetrahydrobiopterin, and its two domains are linked via a regulatory calmodulin-binding domain. Upon calcium-induced calmodulin binding, the reductase and oxygenase domains form a complex, allowing electrons to flow from NADPH via FAD and FMN to the active center. The reductase domain of the enzyme from the bacterium Sorangium cellulosum utilizes a [2Fe-2S] cluster to transfer the electrons from NADPH to the active center. cf. EC 1.14.14.47, nitric-oxide synthase (flavodoxin).
History
created 1992, modified 2012, modified 2017
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1 Oxidoreductases
1.1 Acting on the CH-OH group of donors
1.6.99.4 created 1965, deleted 1972 1.6.99.8 created 1972, deleted 2002 1.6.99.9 created 1972, deleted 2002 1.6.99.10 created 1978, deleted 1981 1.6.99.11 created 1989, deleted 2002 1.6.99.12 created 1989, deleted 2002 1.6.99.13 created 1992, deleted 2002 1.14.13.45 created 1992, deleted 2003
