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).
References
Abe M, Hoshi T, Tajima A (1987) Characteristics of transmural potential changesassociated with the proton-peptideco-transportin toad small intestine. J Physiol 394: 481–499
Abrahamse SL, Bindels RJM, van Os CH (1992) The colon carcinoma cell line Caco-2 contains an H+/K+-ATPase that contributes to intracellular pH regulation. Pflügers Arch 421: 591–597
Boyd CAR, Ward MR (1982) A micro-electrode study of oligopeptide absorption by the small intestinal epithelium of Necturus maculosus. J Physiol 324: 411–428
Ganapathy V, Burckhardt G, Leibach FH (1984) Characteristics of glycylsarcosine transport in rabbit intestinal brush-border membrane vesicles. J Biol Chem 259: 8954–8959
Ganapathy V, Leibach FH (1985) Is intestinal peptide transport energized by a proton gradient? Am J Physiol 249: G153-G160
Kohn PG, Smyth DH, Wright EM (1968) Effects of amino acids, dipeptides and disaccharides on the electrical potential across rat small intestine. J Physiol 196: 723–746
McEwan GTA, Daniel H, Fett C, Burgess MN, Lucas ML (1988) The effect of Escherichia coli STa enterotoxin and other secretagogues on mucosal surface pH of rat small intestine in vivo. Proc R Soc Lond B 234: 219–237
Thwaites DT, Brown CDA, Hirst BH, Simmons NL (1993) Transepithelial glycylsarcosine transport in intestinal Caco-2 cells mediated by expression of H+-coupled carriers at both apical and basal membranes. J Biol Chem 268: 7640–7642
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Thwaites, D.T., McEwan, G.T.A., Hirst, B.H. et al. Transepithelial dipeptide (glycylsarcosine) transport across epithelial monolayers of human Caco-2 cells is rheogenic. Pflugers Arch. 425, 178–180 (1993). https://doi.org/10.1007/BF00374520
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DOI: https://doi.org/10.1007/BF00374520