The biosynthesis of trimethylamine-N-oxide.

Norris and Benoit (1) provided ‘good evidence that injected trimethylamine is converted in the rat to its N-oxide and excreted in the urine. Other mammals have been shown to have the ability to effect the same reaction (2, 3). In a preliminary communication (4), we have reported that hog liver microsomes will catalyze the oxidation of trimethylamine in vitro. The additional requirement for reduced triphosphopyridine nucleotide and oxygen makes this system analogous to a group of microsomal enzyme systems that also catalyze biological oxidations (5). Thus, a study of the oxidation of trimethylamine may yield information on microsomal oxidations in general. In this paper, evidence is presented that the product of trimethylamine oxidation is trimethylamine-N-oxide. Results of experiments to determine optimal conditions for this reaction and the effects of some potential inhibitors and activators are reported.