Structure and pharmacology of proton-linked peptide transporters

The cellular uptake of small peptides such as di-, tri- and tetrapeptides and peptidomimetic drugs proceeds via specialized proton-coupled transporters (Refs. [1-6]). The cDNA clones encoding the oligopeptide transporters PepT1 and PepT2 were recently isolated and were found to constitute a new family of membrane transport proteins. These transporters play important roles in tissues responsible for solute recovery such as epithelial cells of the small intestine and the proximal tubule of the kidney. New insights into the structure and pharmacology of these transporters have been recently obtained based on studies involving Xenopus oocyte expression, electrophysiology and capillary electrophoresis.