The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)



Gene Review

FMO1  -  flavin containing monooxygenase 1

Homo sapiens

Synonyms: Dimethylaniline oxidase 1, FMO 1, Fetal hepatic flavin-containing monooxygenase 1
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of FMO1


High impact information on FMO1


Chemical compound and disease context of FMO1


Biological context of FMO1


Anatomical context of FMO1


Associations of FMO1 with chemical compounds

  • Although (S)-cotinine was observed to inhibit pig FMO1 (Ki = 675 microM), partially purified cDNA-expressed adult human liver FMO3 was not inhibited by (S)-cotinine [20].
  • The I303V variant showed catalytic constants equal to wild-type FMO1 for methimazole and methyl p-tolyl sulfide [2].
  • All the variants demonstrated the same stereoselectivity for methyl p-tolyl sulfide oxidation as wild-type FMO1 [2].
  • CONCLUSIONS: FMO1 and FMO3 catalyse benzydamine N-oxygenation with the highest efficiency [21].
  • FMO1 also metabolized the commonly used insecticide fenthion to its (+)-sulfoxide, with relatively high catalytic efficiency [2].

Regulatory relationships of FMO1

  • The conclusion that FMO was predominantly responsible for trans oxime formation in human liver microsomes was based on the effect of incubation conditions on tyramine N-oxygenation and the observation that cDNA-expressed human FMO3 also N-oxygenated tyramine to give exclusively the trans oxime [22].
  • 2. Thermal inactivation and antibodies to NADPH P450 reductase were used to selectively inactivate FMO and P450 respectively [23].

Other interactions of FMO1

  • For FMO1, FMO2, and FMO3, two to three different splice variants were identified, and their corresponding expression was always low in the tissues examined [24].
  • In this study, we systematically analyzed transcripts of FMO1 to FMO5 in different human tissues by reverse-transcription-polymerase chain reaction and identified a large number of splice variants [24].
  • Activity studies were done with two selective functional FMO substrates, methimazole, and 10-(N,N-dimethylaminopentyl)-2-(trifluoromethyl)phenothiazine and exon 3- (exon 4 for FMO4) deleted FMOs were not able to catalyze the S- and N-oxygenation of these substrates, respectively [24].
  • Localization of human flavin-containing monooxygenase genes FMO2 and FMO5 to chromosome 1q [25].
  • FMO seems to be the major enzymatic oxidant, whereas several P450 enzymes and even reduced hemoglobin are capable of reducing TNO back to TAM [26].

Analytical, diagnostic and therapeutic context of FMO1


  1. Oxidative activation of thiacetazone by the Mycobacterium tuberculosis flavin monooxygenase EtaA and human FMO1 and FMO3. Qian, L., Ortiz de Montellano, P.R. Chem. Res. Toxicol. (2006) [Pubmed]
  2. Evaluation of xenobiotic N- and S-oxidation by variant flavin-containing monooxygenase 1 (FMO1) enzymes. Furnes, B., Schlenk, D. Toxicol. Sci. (2004) [Pubmed]
  3. Cloning, sequencing, distribution, and expression in Escherichia coli of flavin-containing monooxygenase 1C1. Evidence for a third gene subfamily in rabbits. Atta-Asafo-Adjei, E., Lawton, M.P., Philpot, R.M. J. Biol. Chem. (1993) [Pubmed]
  4. Thiourea toxicity in mouse C3H/10T1/2 cells expressing human flavin-dependent monooxygenase 3. Smith, P.B., Crespi, C. Biochem. Pharmacol. (2002) [Pubmed]
  5. Nicotine metabolism in liver microsomes from rats with acute hepatitis or cirrhosis. Nakajima, M., Iwata, K., Yamamoto, T., Funae, Y., Yoshida, T., Kuroiwa, Y. Drug Metab. Dispos. (1998) [Pubmed]
  6. Molecular cloning of the flavin-containing monooxygenase (form II) cDNA from adult human liver. Lomri, N., Gu, Q., Cashman, J.R. Proc. Natl. Acad. Sci. U.S.A. (1992) [Pubmed]
  7. Induction of tamoxifen-4-hydroxylation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), beta-naphthoflavone (beta NF), and phenobarbital (PB) in avian liver: identification of P450 TCDDAA as catalyst of 4-hydroxylation induced by TCDD and beta NF. Kupfer, D., Mani, C., Lee, C.A., Rifkind, A.B. Cancer Res. (1994) [Pubmed]
  8. Cytochrome P-450-mediated activation and irreversible binding of the antiestrogen tamoxifen to proteins in rat and human liver: possible involvement of flavin-containing monooxygenases in tamoxifen activation. Mani, C., Kupfer, D. Cancer Res. (1991) [Pubmed]
  9. Cytochrome P-450- and flavin-containing monooxygenase-catalyzed formation of the carcinogen N-hydroxy-2-aminofluorene and its covalent binding to nuclear DNA. Frederick, C.B., Mays, J.B., Ziegler, D.M., Guengerich, F.P., Kadlubar, F.F. Cancer Res. (1982) [Pubmed]
  10. Expression in Escherichia coli of the flavin-containing monooxygenase D (form II) from adult human liver: determination of a distinct tertiary amine substrate specificity. Lomri, N., Yang, Z., Cashman, J.R. Chem. Res. Toxicol. (1993) [Pubmed]
  11. Size limits of thiocarbamides accepted as substrates by human flavin-containing monooxygenase 1. Kim, Y.M., Ziegler, D.M. Drug Metab. Dispos. (2000) [Pubmed]
  12. Characterization of two human flavin-containing monooxygenase (form 3) enzymes expressed in Escherichia coli as maltose binding protein fusions. Brunelle, A., Bi, Y.A., Lin, J., Russell, B., Luy, L., Berkman, C., Cashman, J. Drug Metab. Dispos. (1997) [Pubmed]
  13. Localization of genes encoding three distinct flavin-containing monooxygenases to human chromosome 1q. Shephard, E.A., Dolphin, C.T., Fox, M.F., Povey, S., Smith, R., Phillips, I.R. Genomics (1993) [Pubmed]
  14. Human flavin-containing monooxygenase: substrate specificity and role in drug metabolism. Cashman, J.R. Curr. Drug Metab. (2000) [Pubmed]
  15. A nomenclature for the mammalian flavin-containing monooxygenase gene family based on amino acid sequence identities. Lawton, M.P., Cashman, J.R., Cresteil, T., Dolphin, C.T., Elfarra, A.A., Hines, R.N., Hodgson, E., Kimura, T., Ozols, J., Phillips, I.R. Arch. Biochem. Biophys. (1994) [Pubmed]
  16. Human hepatic flavin-containing monooxygenases 1 (FMO1) and 3 (FMO3) developmental expression. Koukouritaki, S.B., Simpson, P., Yeung, C.K., Rettie, A.E., Hines, R.N. Pediatr. Res. (2002) [Pubmed]
  17. Regio- and stereoselective oxygenations by adult human liver flavin-containing monooxygenase 3. Comparison with forms 1 and 2. Lomri, N., Yang, Z., Cashman, J.R. Chem. Res. Toxicol. (1993) [Pubmed]
  18. Prochiral sulfides as in vitro probes for multiple forms of the flavin-containing monooxygenase. Rettie, A.E., Meier, G.P., Sadeque, A.J. Chem. Biol. Interact. (1995) [Pubmed]
  19. The molecular biology of the flavin-containing monooxygenases of man. Phillips, I.R., Dolphin, C.T., Clair, P., Hadley, M.R., Hutt, A.J., McCombie, R.R., Smith, R.L., Shephard, E.A. Chem. Biol. Interact. (1995) [Pubmed]
  20. In vitro-in vivo correlations of human (S)-nicotine metabolism. Berkman, C.E., Park, S.B., Wrighton, S.A., Cashman, J.R. Biochem. Pharmacol. (1995) [Pubmed]
  21. In vitro evaluation of potential in vivo probes for human flavin-containing monooxygenase (FMO): metabolism of benzydamine and caffeine by FMO and P450 isoforms. Lang, D.H., Rettie, A.E. British journal of clinical pharmacology. (2000) [Pubmed]
  22. Detoxication of tyramine by the flavin-containing monooxygenase: stereoselective formation of the trans oxime. Lin, J., Cashman, J.R. Chem. Res. Toxicol. (1997) [Pubmed]
  23. Metabolism of thioridazine by microsomal monooxygenases: relative roles of P450 and flavin-containing monooxygenase. Blake, B.L., Rose, R.L., Mailman, R.B., Levi, P.E., Hodgson, E. Xenobiotica (1995) [Pubmed]
  24. Alternative processing events in human FMO genes. Lattard, V., Zhang, J., Cashman, J.R. Mol. Pharmacol. (2004) [Pubmed]
  25. Localization of human flavin-containing monooxygenase genes FMO2 and FMO5 to chromosome 1q. McCombie, R.R., Dolphin, C.T., Povey, S., Phillips, I.R., Shephard, E.A. Genomics (1996) [Pubmed]
  26. Oxidation of tamoxifen by human flavin-containing monooxygenase (FMO) 1 and FMO3 to tamoxifen-N-oxide and its novel reduction back to tamoxifen by human cytochromes P450 and hemoglobin. Parte, P., Kupfer, D. Drug Metab. Dispos. (2005) [Pubmed]
  27. Cloning, primary sequence, and chromosomal mapping of a human flavin-containing monooxygenase (FMO1). Dolphin, C., Shephard, E.A., Povey, S., Palmer, C.N., Ziegler, D.M., Ayesh, R., Smith, R.L., Phillips, I.R. J. Biol. Chem. (1991) [Pubmed]
  28. Investigation of structure and function of a catalytically efficient variant of the human flavin-containing monooxygenase form 3. Borb??s, T., Zhang, J., Cerny, M.A., Lik??, I., Cashman, J.R. Drug Metab. Dispos. (2006) [Pubmed]
  29. Developmental and tissue-specific expression of human flavin-containing monooxygenases 1 and 3. Hines, R.N. Expert opinion on drug metabolism & toxicology. (2006) [Pubmed]
WikiGenes - Universities