Fish trimethylamine

Loechel et al. [20] Trimethylamine Fish Trimethylamine dehydrogenase (TMADH) (Dimethylamine) methylene ferrocene (DMAMFe)... 

Amines occur widely in all living organisms. Trimethylamine, for instance, occurs in animal tissues and is partially responsible for the distinctive odor of fish, nicotine is found in tobacco, and cocaine is a stimulant found in the South American coca bush. In addition, amino acids are the buildingblocks from which all proteins are made, and cyclic amine bases are constituents of nucleic acids. 

Metabolism of trimethylamine oxide in fish muscle involves an enzyme-catalyzed oxidation-reduction reaction. The enzyme responsible for the conversion of trimethylamine oxide to trimethylamine is known as trimethylamine-W-oxide reductase. This enzyme acts on nicotinamide adenine dinucleotide (NADH) and TMAO to produce NAD+, trimethylamine and water (Fig. 13.13.1). TMAO acts as the oxidizing agent and is reduced, while NADH undergoes oxidation as the reducing agent. 

Aside from the complications imposed by the oil in fish and the need to keep the catch cold, there is also a compound in fish called trimethylamine oxide (TMAD), which is converted to trimethylamine (TMA). Trimethylamine oxide is essentially an odorless compound which is ccxiverted by bacteria in and on the fish to the fishy tasting and smelling compound, trimethylamine. Retarding this conversion is one of the prime objectives of adequate cold storage of fishery products (3) (8). 

Sensory. Sensory analysis is one of the oldest accepted methods forjudging seafood quality and freshness. Although fairly accurate, it unfortunately requires trained, experienced panelists to attain accuracy. Perez-Villarreal (( u evaluators experienced in sensory analysis of fish to judge freshness and quality. Results of the study showed sensory scores were better correlated with microbiological analyses, especially total viable counts, than with chemical analyses such as trimethylamine or enine nucleotide decomposition (6). 

Another chemical method for measuring freshness, that is more rapid, continuous, and less destructive than other methods is the detection of volatile trimethylamine (TMA), dimethylamine (DMA), monomethylamine (MMA), and ammonia 14,15). Trimethylamine oxide (TMAO) is a decomposition product of proteins as well as present in excretions of fish 16). Spoilage bacteria can reduce TMAO to TMA plus small amounts of DMA, MMA, and ammonia. Tissue TMA levels have be correlated with the pungent odor associated with spoiled seafood as well as total bacterial counts 14). Researchers incorporated a test strip... 

Zhao, C.Z., Pan, Y.Z., Ma, L.Z., Tang, Z.N., Zhao, G.L., Wang, L.D. (2002) Assay of fish freshness using trimethylamine vapour probe based on a sensitive membrane on piezoelectric quartz crystal. Sens. Actuators B 81 218-222. 

Maschke S, Wahl A, Azaroual N, Boulet O, Crunelle V, Imbenotte M, Foulard M, Vermeersch G, Lhermitte M (1997) 1H-NMR analysis of trimethylamine in urine for the diagnosis of fish odour syndrome. Clin Chim Acta 263 139-146... 

There is also a genetic deficiency in FM03 in humans leading to Fish Odor syndrome, which results from the inability of the afflicted individuals to metabolism trimethylamine, which has a strong fishy smell, to the N-oxide, which has no smell. 

Tertiary amines do not react with nitrous acid, acetyl chloride, benzoyl chloride, benzenesulfonyl chloride, but react with alkyl halides to form quaternary ammonium halides, which are converted by silver hydroxide to quaternary ammonium hydroxides. Quaternary ammonium hydroxides upon heating yield (1) tertiary amine pins alcohol (or, for higher members, olefin plus water). Tertiary amines may also be formed (2) by alkylation of secondary amines, e.g., by dimethyl sulfate, (3) from amino acids by living organisms, e g, decomposition of fish in the case of trimethylamine. 

Beside BAs, low-molecular-weight alkylamines, commonly used as indicators of food quality, can also be present in fish muscle. Tri- and dimethylamine (TMA and DMA) are produced by bacterial reduction of the osmoregulatory substance trimethylamine oxide (TMAO) in fresh marine fish and by enzymatic reduction in frozen storage of gadoid fish (cod, cusk, hake, pollack), with concurrent formation of formaldehyde. 

Trimethylamine, Trimethylamine Fish, meat, fruits, Freshness index... 

K. Mitsubayashi, Y. Kubotera, K. Yano, Y. Hashimoto, T. Kon, S. Nakakura, Y. Nishi and H. Endo, Trimethylamine biosensor with flavin-containing monooxygenase type 3 (FM03) for fish-freshness analysis, Sens. Actuators B Chem., 103(1-2) (2004) 463-467. 

Trimethylamine oxide (TMO) is one of the compounds retained by elasmobranchs to assist their osmotic balance (reviewed by Love, 1970). This compound is also used by eels when they are transferred from fresh water to salt. The fish were not fed, but TMO levels increased for about 24 h. The compound is probably synthesized from choline via trimethylamine, and synthesis of the enzymes responsible for the system appears to begin immediately after transfer to the sea water (Daikoku and Sakaguchi, 1990). 

There are a number of similarities between ammonia and amines that carry beyond the structure. Consider odor. The smell of amines resembles that of ammonia but is not as sharp. However, amines can be quite pungent. Anyone handling or working with raw fish knows how strong the amine odor can be, since raw fish contains low-molecular-weight amines such as dimethylamine and trimethylamine. Other amines associated with decaying flesh have names suggestive of their odors putrescine and cadaverine. 

Any physical exertion or hot weather which makes them sweat soon has those around them quickly moving away. Indeed many victims feel isolated because relationships inevitably break down, and so they try to avoid human contact and often work at home. One person in 10,000 has the faulty gene that is to blame and this was identified in 1999 by Ian Smith and coworkers at Queen Mary College in London. His advice to sufferers is to avoid all fish, red meat, eggs and soya, and eat mainly chicken and salads as the foods least likely to generate trimethylamine in the body. 

Kelly, R.H., and P.H. Yancey (1999). High contents of trimethylamine oxide correlating with depth in deep-sea teleost fishes, skates, and decapod crustaceans. Biol. Bull. 196 18-25. 

Raymond, J.A. (1998). Trimethylamine oxide and urea synthesis in rainbow smelt and some other northern fishes. Physiol. Zool. 71 515-523. 

Raymond, J.A., and A.L. DeVries (1998). Elevated concentrations and synthetic pathways of trimethylamine oxide and urea in some teleost fishes of McMurdo Sound, Antarctica. Fish. Physiol. Biochem. 18 387-398. 

A nitrogen-containing compound, trimethylamine, is produced in a complaint called fish odour syndrome , where the sweat, breath and urine all smell of rotting fish. It is caused by a metabolic liver malfunction and releases trimethylamine in the bowel and gut. Drugs and dietary control can cure the condition. 

Many low molecular weight amines have very foul odors. Trimethylamine [(CH3)3N], formed when enzymes break down certain fish proteins, has the characteristic odor of rotting fish. Putrescine (NH2CH2CH2CH2CH2NH2) and cadaverine (NH2CH2CH2CH2CH2CH2NH2) are both poisonous diamines with putrid odors. They, too, are present in rotting fish, and are partly responsible for the odors of semen, urine, and bad breath. 

Many of the amines have a fishy smell, and as early as 1851 trimethylamine was isolated by distillation of herring with lime and was called fish-gas . Methylamine CH3NH2 Ethylamine C2H5NH2 Phenylamine QH5NH2 Dimethylamine (CH,)2NH Methylethylamine (CH3)(C2H5)NH Trimethylamine (CH3)3N R Tetramethylammonium ion (CH3>4N ... 

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