IUBMB Enzyme Nomenclature


Accepted name: trimethylamine monooxygenase

Reaction: N,N,N-trimethylamine + NADPH + H+ + O2 = N,N,N-trimethylamine N-oxide + NADP+ + H2O

Other name(s): flavin-containing monooxygenase 3; FMO3; tmm (gene name)

Systematic name: N,N,N-trimethylamine,NADPH:oxygen oxidoreductase (N-oxide-forming)

Comments: A flavoprotein. The bacterial enzyme enables bacteria to use trimethylamine as the sole source of carbon and energy [1,4]. The mammalian enzyme is involved in detoxification of trimethylamine. Mutations in the human enzyme cause the inheritable disease known as trimethylaminuria (fish odor syndrome) [2,3].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Large, P.J., Boulton, C.A. and Crabbe, M.J. The reduced nicotinamide-adenine dinucleotide phosphate- and oxygen-dependent N-oxygenation of trimethylamine by Pseudomonas aminovorans. Biochem. J. 128 (1972) 137P-138P. [PMID: 4404764]

2. Dolphin, C.T., Riley, J.H., Smith, R.L., Shephard, E.A. and Phillips, I.R. Structural organization of the human flavin-containing monooxygenase 3 gene (FMO3), the favored candidate for fish-odor syndrome, determined directly from genomic DNA. Genomics 46 (1997) 260-267. [PMID: 9417913]

3. Treacy, E.P., Akerman, B.R., Chow, L.M., Youil, R., Bibeau, C., Lin, J., Bruce, A.G., Knight, M., Danks, D.M., Cashman, J.R. and Forrest, S.M. Mutations of the flavin-containing monooxygenase gene (FMO3) cause trimethylaminuria, a defect in detoxication. Hum. Mol. Genet. 7 (1998) 839-845. [PMID: 9536088]

4. Chen, Y., Patel, N.A., Crombie, A., Scrivens, J.H. and Murrell, J.C. Bacterial flavin-containing monooxygenase is trimethylamine monooxygenase. Proc. Natl. Acad. Sci. USA 108 (2011) 17791-17796. [PMID: 22006322]

[EC created 2012]

Return to EC 1.14.13 home page
Return to EC 1.14 home page
Return to EC 1 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page