“Furthermore, the addition of levorphanol to membrane vesicles preloaded to the steady state with proline produces a marked net efflux of proline.”
“ Levorphanol inhibits the transport of the amino acids proline and lysine by cytoplasmic membrane vesicles derived from Escherichia coli.”
“The effect is independent of the energy source, since levorphanol inhibits proline uptake to the same extent in the presence of 20 mM d-lactate or 20 mM succinate and in the absence of an exogenous energy source.”