Catalyzes the efflux of L-methionine. Can also export L-leucine, L-isoleucine and L-valine. Activity is dependent on electrochemical potential. Efflux is inhibited by carbonyl cyanide m-chlorophenylhydrazone (CCCP). Induced in the presence of intracellular L-methionine, L-leucine or L-isoleucine. Deletion increases the susceptibility to DL-ethionine, DL-norleucine and DL-norvaline. Deletion also results in intracellular accumulation and a reduced rate of export of methionine in the presence of extracellular Met-Met dipeptides. Belongs to the amino acid-polyamine-organocation (APC) superfamily. Amino acid efflux (AAE) (TC 2.A.3.13) family.