Lipotropic activity and toxicity of methoxinine (oxymethionine).

Methoxinine (nn-2-amino-4-methoxybutanoic acid) has been synthesized by Roblin and coworkers (l), who studied its action on Escherichia coli and Staphylococcus aureus. The growth-inhibitory effect of this compound was prevented by L-methionine but not by the D isomer. 1 mole of nnmethionine reversed the antibacterial action of 500 to 1000 moles of DLmethoxinine. In combination with sulfonamides a synergistic bacteriostatic effect was produced by methoxinine. Methoxinine was of interest to this laboratory as a tool in an investigation of the protective action afforded by methionine against the hepatotoxic effects of certain chemicals in protein-deficient states. Provided certain conditions were fulfilled, it might be possible by the use of the oxygen analogue to distinguish between any effect of methionine due to its sparing or replenishment of sulfhydryl enzyme systems (2) and such effect as might result solely from its role as a lipotropic factor (3). Before such a demonstration might be made, however, it was first necessary to establish that methoxinine does possess lipotropic activity, in addition to being devoid of toxic manifestations that might otherwise complicate the experiment. The work described in the present report shows that the lipotropic activity does indeed exist, but that methoxinine exhibits an order of toxicity that would probably preclude its use in the connection indicated.