Peptide mimics as substrates for the intestinal peptide transporter

Catherine S. Temple, Andrew K. Stewart, David Meredith, Norma A. Lister, Keith M. Morgan, Ian D. Collier, Richard D. Vaughan-Jones, C. A R Boyd, Patrick D. Bailey, J. Ramsey Bronk

Research output: Contribution to journalArticlepeer-review

72 Citations (Scopus)


4-Aminophenylacetic acid (4-APAA), a peptide mimic lacking a peptide bond, has been shown to interact with a proton-coupled oligopeptide transporter using a number of different experimental approaches. In addition to inhibiting transport of labeled peptides, these studies show that 4.APAA is itself translocated. 4-APAA transport across the rat intact intestine was stimulated 18-fold by luminal acidification (to pH 6.8) as determined by high performance liquid chromatography (HPLC); in enterocytes isolated from mouse small intestine the intracellular pH was reduced on application of 4-APAA, as shown fluorimetrically with the pH indicator carboxy-SNARF; 4-APAA trans- stimulated radiolabeled peptide transport in brush-border membrane vesicles isolated from rat renal cortex; and in Xenopus oocytes expressing PepT1, 4- APAA produced trans-stimulation of radiolabeled peptide efflux, and as determined by HPLC, was a substrate for translocation by this transporter. These results with 4-APAA show for the first time that the presence of a peptide bond is not a requirement for rapid translocation through the proton- linked oligopeptide transporter (PepT1). Further investigation will be needed to determine the minimal structural requirements for a molecule to be a substrate for this transporter.

Original languageEnglish
Pages (from-to)20-22
Number of pages3
JournalJournal of Biological Chemistry
Issue number1
Publication statusPublished - 2 Jan 1998


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