PMID: 7931699Oct 1, 1994Paper

Mechanisms and kinetics of uptake and efflux of L-methionine in an intestinal epithelial model (Caco-2)

The Journal of Nutrition
J ChenM Hu

Abstract

Mechanism and kinetics of uptake and efflux of L-methionine in a human intestinal epithelial model system (Caco-2) were studied to understand the transcellular transport process and to determine its rate-limiting step. The kinetic studies indicated that uptakes from both the apical and basolateral sides were saturable [for apical uptake: Km = 0.96 mmol/L, maximum flux = 673 pmol/(min.cm2); for basolateral uptake: Km = 3.46 mmol/L, maximum flux = 3480 pmol/(min.cm2)], whereas the efflux from these two membranes was apparently linear for intracellular concentrations < 6.5 mmol/L [for apical efflux, the apparent first-order rate constant = 1.01 x 10(-4) cm/min; for basolateral efflux, the rate constant = 1.78 x 10(-4) cm/min]. The results of inhibition studies indicate the apical uptake is partially active and Na(+)-dependent via a combination of amino acid transport systems B0,+ and ASC, which is somewhat different from the less energy- and Na(+)-dependent basolateral uptake. The basolateral uptake is also more dependent on system L and exhibits high counter-exchange capability. Finally, the rate-limiting step in the apical to basolateral transport of methionine is determined to be the basolateral efflux.

Citations

May 12, 1998·The Journal of Physiology·J F Soriano-GarcíaM Moreto
Jul 12, 2001·American Journal of Physiology. Gastrointestinal and Liver Physiology·S UgawaS Shimada
Oct 23, 2004·Drug Metabolism and Pharmacokinetics·Nobuhiro NishimuraKikuo Iwamoto
Sep 10, 2005·The Journal of Membrane Biology·S Roig-PérezR Ferrer
Jan 16, 2009·American Journal of Physiology. Cell Physiology·Raquel Martín-VenegasRuth Ferrer
Feb 5, 2003·Journal of Biomedical Science·Godfrey Tunnicliff
Nov 18, 2010·Journal of Drug Targeting·Sheraz KhanAfzal R Mohammed
Apr 8, 2009·The Journal of Membrane Biology·Sònia Roig-PérezRuth Ferrer
Oct 19, 2016·IUBMB Life·Lucia MastrototaroJörg R Aschenbach
Oct 22, 2002·American Journal of Physiology. Lung Cellular and Molecular Physiology·Jennifer L SloanSela Mager
Feb 24, 2015·Nutrients·Karolina A P WijnandsMartijn Poeze
Jan 23, 2021·Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology·Van Pham Thi Ha ToMatthew E Loewen
Mar 7, 2009·Chemical Reviews·Stefan Balaz
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