Abstract
Net transepithelial transport (and cellular accumulation) of the dipeptide glycylsarcosine (Gly-Sar), across the apical membrane of human intestinal Caco-2 epithelia, is driven by a proton gradient (Na(+)-free conditions) and displays saturation kinetics (Km 17.4 +/- 5.1 mM, Vmax of 92.8 +/- 15.6 nmol.cm-2.h-1). Net Gly-Sar transport is associated with the stimulation of an inward short-circuit current (Isc). This dipeptide-stimulated Isc is observed in both Na(+)-containing and Na(+)-free conditions, is stimulated by apical acidity, and displays saturation kinetics (in Na(+)-free media at apical pH 6.0, Km of 13.6 +/- 4.5 mM and a Vmax of 284.1 +/- 39.3 nmol.cm-2.h-1). The maximal capacities of Gly-Sar transport and Isc suggest a dipeptide/proton stoichiometry greater than unity (1:3).
Original language | English |
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Pages (from-to) | 178-80 |
Number of pages | 3 |
Journal | Pflugers Archiv : European Journal of Physiology |
Volume | 425 |
Issue number | 1-2 |
Publication status | Published - Oct 1993 |
Keywords
- Biological Transport
- Cell Line
- Dipeptides
- Electric Conductivity
- Epithelium
- Humans
- Hydrogen-Ion Concentration
- Intestines
- Kinetics
- Protons