Transepithelial Transport of the in Human Intestinal Caco - 2 CellBioactive Tripeptide , Monolayers Val - Pro - Pro , Makoto

these tripeptides was studied by using monolayercultured human intestinaJ Caco-2 cells which express rnany enterocyte-Iike functions including the peptide transporter(PepTl)-mediated transport system. ValPro-Pro, an ACE-inhibitors peptide from fermented milk, was used as a model tripeptide. A significant amount of intact Val-Pro-Pro was transported across the Caco-2 cel) monolayer. This transport was hardly inhibited by a competitiye substrate for PepTl. Since no intact Val-Pro-Pro was detected in the cells, Val-ProPro apically taken by Caco-2 cells via PepTl was likely to havc been quickly hydrolyzcd by intraccllular peptidases, producing free Val and Pro. These findings suggest that PepTl-mediated transport was not inyolved in the transepithelial transport of intact Val-Pro-Pro. Paracellular diffusie" is suggested to haye been the main mechanism for the transport of intact Val-Pro-Pro across the Caco-2 cett monolayer.