Reaction: NAD(P)H + H+ + O2 = NAD(P)+ + H2O2
Other name(s): THOX2; ThOX; dual oxidase; p138tox; thyroid NADPH oxidase; thyroid oxidase; thyroid oxidase 2; NADPH oxidase; NAD(P)H:oxygen oxidoreductase; NAD(P)H oxidase
Systematic name: NAD(P)H:oxygen oxidoreductase (H2O2-forming)
Comments: Requires FAD, heme and calcium. When calcium is present, this transmembrane glycoprotein generates H2O2 by transfering electrons from intracellular NAD(P)H to extracellular molecular oxygen. The electron bridge within the enzyme contains one molecule of FAD and probably two heme groups. This flavoprotein is expressed at the apical membrane of thyrocytes, and provides H2O2 for the thyroid peroxidase-catalysed biosynthesis of thyroid hormones.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 77106-92-4
References:
1. Moreno, J.C., Bikker, H., Kempers, M.J., van Trotsenburg, A.S., Baas, F., de Vijlder, J.J., Vulsma, T. and Ris-Stalpers, C. Inactivating mutations in the gene for thyroid oxidase 2 (THOX2) and congenital hypothyroidism. N. Engl. J. Med. 347 (2002) 95-102. [PMID: 12110737]
2. De Deken, X., Wang, D., Dumont, J.E. and Miot, F. Characterization of ThOX proteins as components of the thyroid H2O2-generating system. Exp. Cell 273 (2002) 187-196. [PMID: 11822874]
3. De Deken, X., Wang, D., Many, M.C., Costagliola, S., Libert, F., Vassart, G., Dumont, J.E. and Miot, F. Cloning of two human thyroid cDNAs encoding new members of the NADPH oxidase family. J. Biol. Chem. 275 (2000) 23227-23233. [PMID: 10806195]
4. Dupuy, C., Ohayon, R., Valent, A., Noel-Hudson, M.S., Deme, D. and Virion, A. Purification of a novel flavoprotein involved in the thyroid NADPH oxidase. Cloning of the porcine and human cDNAs. J. Biol. Chem. 274 (1999) 37265-37269. [PMID: 10601291]
5. Leseney, A.M., Deme, D., Legue, O., Ohayon, R., Chanson, P., Sales, J.P., Pires de Carvalho, D., Dupuy, C. and Virion, A. Biochemical characterization of a Ca2+/NAD(P)H-dependent H2O2 generator in human thyroid tissue. Biochimie 81 (1999) 373-380. [PMID: 10401672]
6. Dupuy, C., Virion, A., Ohayon, R., Kaniewski, J., Deme, D. and Pommier, J. Mechanism of hydrogen peroxide formation catalyzed by NADPH oxidase in thyroid plasma membrane. J. Biol. Chem. 266 (1991) 3739-3743. [PMID: 1995628]