Pept1

Among the different families of transporter only two occur ubiquitously in all classifications of organisms. These are the ATP-Binding Cassette (ABC) superfamily and the Major Facilitator Superfamily (MFS). The MFS transporters are single-polypeptide secondary carriers capable only of transporting small solutes in response to chemiosmotic ion gradients .

Oligopeptide transporter, peptide:H+ symporter supports the proton-coupled intake of oligopeptides of 2 to 4 amino acids. These proteins may constitute a major route for the absorption of the end products of protein digestion.

The transport of peptides into cells is a well-documented biological phenomenon which is accomplished by specific, energy-dependent transporters found in a number of organisms as diverse as bacteria and humans. The PTR family of proteins is distinct from the ABC-type peptide transporters and was uncovered by sequence analyses of a number of recently discovered peptide transport proteins . These proteins that seem to be mainly involved in the intake of small peptides with the concomitant uptake of a proton .

These integral membrane proteins are predicted to comprise twelve transmembrane regions.