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Molecular structure and tissue distribution
Peptide transporter 1 (SLC15A1) as a low affinity and high capacity transporter mainly localized in the apical membrane of enterocyte of the small intestine and in S1-segment epithelial cells of renal proximal tubule.
The open reading frame of hPEPT1 encodes 708 amino acids with 70% similarity to the high-affinity transporter isoform PEPT2. The amino acid sequence predicts 12 transmembrane domains in PEPT1 with both amino and carboxy termini facing the cytoplasmic side.

Interaction of hPEPT1 with endogenous compounds and drugs
The physiological relevance of PEPT1 is the absorption of nutritional nitrogen sources in the enterocytes and renal reabsorption of peptides after glomerular filtration from the primary urine. The PEPT1 has an enormous range of substrate specificity including 400 dipeptides and 8000 tripeptides physiologically occurring. Peptides consisting of L-amino acid are preferred over those containing individual D-amino acid residues.
PEPT1 operates as H+-coupled symporter of a broad range di- and tripeptides, including zwitterionic, anionic and cationic peptides. In addition, PEPT1 mediate the uptake of a variety of drugs because of their sterical resemblance to di- and tripeptides like -lactam antibiotics (e.g. cefadroxil, amoxicillin), angiotensin-converting enzyme inhibitor (enalapril), protease inhibitor (bestatin), and virostatica (valacyclovir). One of the most commonly used reference substrates of the H+/peptide cotransporter is [14C]glycylsarcosine (Gly-Sar). The uptake of Gly-Sar by PEPT1 could be inhibited with fosinopril, losartan, irbesatan and valsartan.




New validated products:

  • mNtcp
  • mOct1


3rd German Pharm-Tox Summit
Göttingen, Germany
26 February - 1 March 2018

Saarbrücken, Germany
8 March 2018


AAPS Workshop
Virginia, USA
16 - 18 April 2018


20th Barrier- and

Bad Herrenalb, Germany
7 - 9 May 2018

Greifswalder Transporttage 2018
Greifswald, Germany
7 - 9 September 2018


Guidance for Industry (FDA and EMA)