aspect of the problem. 



Trlmethylamine oxide as a methyl donor and Its relationship to 

 other methylated compounds . — Barrenscheen and Pajatlitschko (1950) have 

 shown that trimethylamine oxide acts as a methyl donor for the synthesis 

 of choline in the muscle brei of guinea pig. This system, which is called 

 cholinepherase, has not been reported in marine animals. 



Since trimethylamine eind trimethylamine oxide do not prevent 

 lipotropic changes in the livers of experimental animals as does choline 

 (Moyer and du Vigneaud 19^2), the transmethylation functions that have 

 been given to choline have not been ascribed to trimethylamine oxide 

 (Arnstein 1955). 



Bach (l9'4-5) suggests that some marine suiimals possess a large 

 methylating capacity, as is shown by the occurrence of tetramine. 



r(cH3)i, hT", 



in the Actinia (sea anemone). A number of other methylated 



compounds have been found in marine animals. Seme of these are choline, 

 glycine betaine, gamma-butyrobetaine, homarine, trigonelline, stachydrine 

 (Shewan 1951), dimethyl thetin (Patton I958), methionine, and dimethyl- 

 be taine (Welsh and Prock I958) . 



Other tertisiry amine oxides . — Tertiary amine oxides, the family 

 of compounds to which trimethylamine oxide belongs, are known to occur 

 as components of plants and animals (Fish, Sweeley, and Horning 1956) . 

 It is not known, however, what the function of these oxides might be in 

 the plants eind animals. The frequency with which they occur in living 

 organisms suggests that they are something more than terminal oxidation 

 products of amines (Fish, Johnson, and Horning 1956) . It has been found 

 possible to carry out a ferric-ion induced rearrangement of tertiary- 

 amine oxides under mild conditions to yield as products a secondary amine 

 plus formaldehyde or formic acid. This rearrsuagement has been shown for 

 N,H-dimethyl-tryptamine oxide (Fish, Johnson, and Horning 1956) and 

 trimethylamine oxide (Vaisey I956) . 



Formation of trimethylamine oxide in mnmmals as a result of 

 degradation of choline or choline-containing derivatives . — Choline fed to 

 rats is excreted in the urine as trimethylamine oxide (De la Huerga and 

 Popper 1952, Korris and Benoit 19^5b). This is caused by bacterial 

 breakdown of choline to trimethylamine in the intestinal tract (Dyer euid 

 Wood 19^7); and following absorption, the trimethylamine is converted to 

 the oxide by trimethylamine oxidase. Very small amo\ints of trimethylamine 

 oxide and trimethylamine are present in mammal tissues; however, no 

 function has been reported for these compounds. 



SUMMARY 



Trimethylamine oxide has been reported in a coelenterate, an 

 echinoderm, some molluscs, all crustaceans, all elasmobranchs , most 



16 



