Formation of γ‐butyrobetaine and trimethylamine from quaternary ammonium compounds structure‐related to l‐carnitine and choline by Proteus vulgaris

¥-Butyrobetaine (4-trimethylaminobutyrate) is the direct precursor of L-carnitine (4-trimethylamino-3-hydroxybutyrate) in its biosynthesis in microorganisms and in mammals [1]. Recently, we have shown that various members of the Enterobacteriaceae, including Proteus vulgaris, are capable of retransforming L-carni t ine into ~,butyrobetaine [2]. Reduction of the physiological concentration of L-carnitine in man leads to an L-carnit ine deficiency syndrome [3]. Microorganisms of the gastrointestinal tract can play a role in lowering the carnitine concentration by catabolism of the food carnitine. In the present study, the stability of physiological carnitine derivatives, and structurally related trimethylammonium compounds, to attacks by P. vulgaris was tested in a complex medium under partially anaerobic conditions. During catabolism of carnitine. c ro tonobeta ine ( 4 t r i m e t h y l a m i n o 2 butenoate) occurred as an intermediary product. It served as a hydrogen acceptor and, like fumarate [4], significantly stimulated the growth of P. t)ulgaris. 2. MATERIAL AND METHODS