Trimethylamine N-oxide

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Trimethylamine N-oxide, also known as trimethylamine oxide, abbreviated as TMAO and TMANO, is an oxidation product of trimethylamine and a common metabolite in animals.

Trimethylamine oxide is a naturally occurring osmolyte that occurs in saltwater fish, sharks and rays, molluscs, and crustaceans. They use this osmolyte, along with free amino acids, to reduce the 3% saltiness of seawater to the desirable 1% of dissolved solids inside cells. TMAO decomposes to trimethylamine (TMA) which is the main odorant causing the characteristic smell of degrading seafood.

Trimethylaminuria is a defect in the production of the enzyme Flavin containing monooxygenase 3 (FMO3) ^[1][2], causing incomplete breakdown of trimethylamine from choline containing food into trimethylamine oxide. Trimethylamine then builds up and is released in the person's sweat, urine, and breath, giving off a strong fishy odor.

Trimethylamine oxide is used in protein folding experiments to counteract the unfolding effects of urea. ^[3]

[edit] References

1. ^ Treacy EP, et al. (1998). "Mutations of the flavin-containing monooxygenase gene (FMO3) cause trimethylaminuria, a defect in detoxication". Human Molecular Genetics 7 (5): 839–45. doi:10.1093/hmg/7.5.839. 
2. ^ Zschocke J, Kohlmueller D, Quak E, Meissner T, Hoffmann GF, Mayatepek E (1999). "Mild trimethylaminuria caused by common variants in FMO3 gene". Lancet 354 (9181): 834–5. PMID 10485731. 
3. ^ Zou, Q., et al (2002). "The Molecular Mechanism of Stabilization of Proteins by TMAO and Its Ability to Counteract the Effects of Urea". Journal of American Chemical Society 124 (7): 1192. doi:10.1021/ja004206b.