Do neutral amino acids and their N-methylated analogues share the same Na-dependent carrier in brush-border membrane from the eel intestine?

1. 1. Kinetics of Na-neutral amino acid cotransport by brush-border membrane vesicles from the eel (Anguilla anguilla) intestine was studied. 2. 2. The substrate-dependent Na-influx was estimated by monitoring the decay of a preset inside negative membrane potential with a voltage-sensitive fluorescent dye. 3. 3. N-Methylglycine, N-methylalanine and α-(methylamino)-isobutyric acid are transported by the Na-dependent carrier responsible for proline translocation. This carrier is distinct from the one responsible for glycine, alanine and α-aminoisobutyric acid translocation.