Trimethylamine oxide, betaine and other osmolytes in deep-sea animals: depth trends and effects on enzymes under hydrostatic pressure.
Most shallow teleosts have low organic osmolyte contents, e.g. 70 mmol/kg or less of trimethylamine oxide (TMAO). Our previous work showed that TMAO contents increase with depth in muscles of several Pacific families of teleost fishes, to about 180 mmol/kg wet wt at 2.9 km depth in grenadiers. We now report that abyssal grenadiers (Coryphaenoides armatus, Macrouridae) from the Atlantic at 4.8 km depth contain 261 mmol/kg wet wt in muscle tissue. This precisely fits a linear trend extrapolated from the earlier data. We also found that anemones show a trend of increasing contents of methylamines (TMAO, betaine) and scyllo-inositol with increasing depth. Previously we found that TMAO counteracts the inhibitory effects of hydrostatic pressure on a variety of proteins. We now report that TMAO and, to a lesser extent, betaine, are generally better stabilizers than other common osmolytes (myo-inositol, taurine and glycine), in terms of counteracting the effects of pressure on NADH Km of grenadier lactate dehydrogenase and ADP Km of anemone and rabbit pyruvate kinase.
Yancey
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Biology Department, Whitman College, Walla Walla, WA 99362, USA. yancey@whitman.edu
Rhea
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Kemp
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Bailey
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D000222:Adaptation, Physiological; D031883:Anemone; D000818:Animals; D001622:Betaine / Q000032:analysis; D004795:Enzyme Stability; D004798:Enzymes; D048388:Gadiformes; D006874:Hydrostatic Pressure; D007294:Inositol / Q000031:analogs & derivatives / Q000032:analysis; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008386:Marine Biology; D008744:Methylamines / Q000032:analysis; D018482:Muscle, Skeletal / Q000737:chemistry; D009994:Osmolar Concentration; D011770:Pyruvate Kinase / Q000378:metabolism*
D004798:Enzymes; D008744:Methylamines; D001622:Betaine; D007294:Inositol; D007770:L-Lactate Dehydrogenase; D011770:Pyruvate Kinase; C005855:trimethyloxamine