Enhancement of the small intestinal uptake of phenylalanylglycine via a H+/oligopeptide transport system by chemical modification with fatty acids.

T Fujita, Y Morishita, H Ito, D Kuribayashi, A Yamamoto, S Muranishi

Index: Life Sci. 61(25) , 2455-65, (1997)

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Abstract

The transport characteristics of chemically modified phenylalanylglycine (Phe-Gly) with butyric acid (C4-Phe-Gly) and caproic acid (C6-Phe-Gly) were examined using rabbit intestinal brush-border membrane vesicles (BBMVs). In the presence of an inwardly H+ gradient (pH 7.5 inside, pH 6.0 outside), the uptake of Phe-Gly via BBMVs was significantly enhanced by the covalent attachment of butyric or caproic acid to the N-terminal of Phe-Gly. Moreover, C4-Phe-Gly uptake was stimulated by the trans-stimulation effect of some dipeptides and cefadroxil, and was inhibited by other dipeptides and cefadroxil. These results indicate that N-terminal modified Phe-Gly with fatty acids are transported into BBMVs via an oligopeptide transporter. Therefore, chemical modification of dipeptides with fatty acids can enhance the intestinal absorption of dipeptide by a carrier-mediated transport via an oligopeptide transporter.