Splitting of the C-N bond in carnitine by an enzyme (trimethylamine forming) from membranes of Acinetobacter calcoaceticus

Some bacteria, e.g. from the genera Vibrio, Serratia, Pseudomonas or Proteus, are able, with species-specific variations, to form trimethylamine (TMA) from quaternary ammonium compounds such as choline, glycine betaine, and carnitine [1-5]. Although TMA causes problems in fisheries, veterinary medicine, and human medicine, because of its fishy odour and its toxicity [6,7], little is known about the enzymes which participate in its formation by splitting the C N bond of the original compounds. Intact cells of Acinetobacter calcoaceticus, a bacterium capable of growing on n-alkanes [8], split the C N of L( -)-carnitine and utilize the carbon skeleton as the sole C-source [9,10]. This paper describes the detection of the splitting activity in cell-free extracts of A. calcoaceticus, the substrate specificity of the TMA-forming enzyme, and its induction by growth on DL-carnitine.