Amino Acids

, Volume 31, Issue 2, pp 119–136

Transport of L-proline, L-proline-containing peptides and related drugs at mammalian epithelial cell membranes


  • M. Brandsch
    • Membrane Transport Group, BiozentrumMartin-Luther-University Halle-Wittenberg
Review Article

DOI: 10.1007/s00726-006-0307-0

Cite this article as:
Brandsch, M. Amino Acids (2006) 31: 119. doi:10.1007/s00726-006-0307-0


Membrane transport of L-proline has received considerable attention in basic and pharmaceutical research recently. Of the most recently cloned members of the solute carrier family, two are “proline transporters”. The amino acid transporter PAT1, expressed in intestine, kidney, brain and other organs, mediates the uptake of proline and derivatives in a pH gradient-dependent manner. The Na+-dependent proline transporter SIT1, cloned in 2005, exhibits the properties of the long-sought classical IMINO system. Proline-containing peptides are of interest for several reasons. Many biologically important peptide sequences contain highly conserved proline residues. Xaa-Pro peptides are very often resistant to enzymatic hydrolysis and display, in contrast to Pro-Xaa peptides, a high affinity to the H+/peptide cotransporter PEPT1 which is expressed in intestinal, renal, lung and biliary duct epithelial cells. Furthermore, several orally available drugs are recognized by PEPT1 as Xaa-Pro analogues due to their sterical resemblance to small peptides.

Keywords: Membrane transport – Imino acids – Proline derivatives – Peptides – PEPT1 – PEPT2 – PAT1 – SIT1 – Proton gradient

Copyright information

© Springer-Verlag 2006