Trimethylamine oxide
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| General | ||||||||||
| Surname | Trimethylamine oxide | |||||||||
| other names |
Trimethylamine- N -oxide |
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| Molecular formula | C 3 H 9 NO | |||||||||
| Brief description |
colorless to yellow, odorless solid |
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| properties | ||||||||||
| Molar mass | 75.11 g mol −1 | |||||||||
| Physical state |
firmly |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||
Trimethylamine oxide ( TMAO ), more precisely trimethylamine- N -oxide , is an amine oxide . It occurs as an osmolyte in the cells of animals living in salt water: cartilaginous fish , i.e. sharks, rays and molluscs and crustaceans. These animals use the substance to be iso-osmotic with seawater without having to store appropriate concentrations of soluble salt ions intracellularly. Through microbial degradation, TMAO becomes trimethylamine , which causes the typical fish odor (see also occurrence of amines and fish odor disease).
Stabilization of proteins against hydrostatic pressure
Trimethylamine- N -oxide stabilizes proteins in cells of fish against the increasing hydrostatic pressure with depth . The average concentration of TMAO in real bony fish increases from 40 mmol / kg at a depth of 0 m to 261 mmol / kg at a depth of 4850 m. This increases the internal osmolality in the fish cells with increasing habitat depth . The highest TMAO concentration to date was measured with 386 mmol / kg in the bell-bellied fish Notoliparis kermadecensis at a depth of 7000 m in the Kermadec Trench, which corresponds to an osmolality of 991 mOsmol / kg. In November 2017, Pseudoliparis swirei, a member of the disc bellies family, was observed in the Mariana Trench at depths of up to 8,098 meters ; in the Puerto Rico Trench , only one dead specimen of Abyssobrotula galatheae was recovered at a depth of 8,370 meters . These observations confirm the hypothesis that these fish cannot live below a depth of around 8,200 m for biochemical reasons: Higher TMAO concentrations would stabilize the proteins in the cell such as myosin, which is responsible for muscle movements, to such an extent that they no longer function could perceive. Furthermore, the osmolality of seawater there reaches 1100 mOsmol / kg and at higher TMAO concentrations in the cells, seawater would flow into the tissue. The synthesis of TMAO by the enzyme flavin monooxygenase 3 was examined more closely by Chinese researchers in 2019 in the genome of Pseudoliparis swirei from the Mariana Trench.
Freezing point depression of proteins
In some Antarctic and arctic bony fish, trimethylamine- N -oxide takes on the function of an antifreeze : Concentrations in the range of a few mmol·l −1 make a significant contribution to lowering the freezing point of body fluids.
Web links
- BA Seibel, PJ Walsh: Trimethylamine oxide accumulation in marine animals: relationship to acylglycerol storage. In: The Journal of experimental biology. Volume 205, Pt 3 February 2002, ISSN 0022-0949 , pp. 297-306, PMID 11854367 (review). - English paper on the osmoregulatory role in marine animals
- Fish swim deeper than 8000 meters , Spiegel Online from March 5, 2014
Individual evidence
- ↑ a b Entry trimethylamine oxide at The Good Scents Company , accessed April 7, 2015.
- ↑ Data sheet Trimethylamine N-oxide dihydrate from Sigma-Aldrich , accessed on May 14, 2017 ( PDF ).
- ↑ a b Data sheet Trimethylamine N-oxide from Sigma-Aldrich , accessed on April 24, 2011 ( PDF ).
- ↑ Jonathan Amos: Fishy molecule sets depth limit. BBC, March 4, 2014, accessed March 5, 2014 .
- ↑ PH Yancey, ME Gerringer, JC Drazen, AA Rowden, A. Jamieson: Marine fish may be biochemically constrained from inhabiting the deepest ocean depths . In: Proceedings of the National Academy of Sciences . tape 111 , no. 12 , March 25, 2014, p. 4461-4465 , doi : 10.1073 / pnas.1322003111 .
- ↑ Kun Wang, Yanjun Shen et al. a .: Morphology and genome of a snailfish from the Mariana Trench provide insights into deep-sea adaptation , in Nature , April 15, 2019, pp. 823 - 833 [1]
- ↑ Jason R. Treberg, Connie E. Wilson, Robert C. Richards, K. Vanya Ewart, William R. Driedzic : The freeze-avoidance response of smelt Osmerus mordax: initiation and subsequent suppression of glycerol, trimethylamine oxide and urea accumulation . In: The Journal of Experimental Biology . tape 205 , 2002, p. 1419-1427 ( PDF ).