Transport of free and peptide-bound pyrraline at intestinal and renal epithelial cells.
Pyrraline is a quantitatively dominating glycation compound of the advanced Maillard reaction in foods and can be found in urine after consumption of pyrraline-containing food items. The purpose of this study was to investigate the transport of pyrraline and its dipeptide derivatives alanylpyrraline (Ala-Pyrr) and pyrralylalanine (Pyrr-Ala) at intestinal and renal cell lines. Pyrraline inhibited the l-[(3)H]lysine uptake with IC(50) values of 0.3 mM (Caco-2 cells) and 3.5 mM (OK cells), respectively, but not the uptake of [(14)C]Gly-Sar (Caco-2 and SKPT cells). In contrast, Ala-Pyrr strongly inhibited the uptake of [(14)C]Gly-Sar in Caco-2 and SKPT cells with IC(50) values of 0.19 and 0.017 mM, respectively. Pyrr-Ala inhibited the carrier-mediated uptake of [(14)C]Gly-Sar in Caco-2 and SKPT cells by 50% at concentrations of 0.03 and 0.008 mM, respectively. The transepithelial flux of peptide-bound pyrraline across Caco-2 cell monolayers was up to 15-fold higher compared to the flux of free pyrraline. We conclude that free pyrraline is not a substrate for the intestinal lysine transporter and that the absorption of dietary pyrraline occurs most likely in the form of dipeptides rather than as the free amino acid.
Hellwig
Michael
M
Institute of Food Chemistry, Technische Universität Dresden, D-01062 Dresden, Germany.
Geissler
Stefanie
S
Peto
Anett
A
Knütter
Ilka
I
Brandsch
Matthias
M
Henle
Thomas
T
D000409:Alanine / Q000378:metabolism; D026905:Amino Acid Transport Systems / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D018938:Caco-2 Cells; D002460:Cell Line; D004151:Dipeptides / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D007687:Kidney Tubules, Proximal; D008239:Lysine / Q000378:metabolism; D009646:Norleucine / Q000031:analogs & derivatives* / Q000378:metabolism; D009893:Opossums; D010455:Peptides / Q000378:metabolism*; D011758:Pyrroles / Q000378:metabolism*; D051381:Rats
D026905:Amino Acid Transport Systems; D004151:Dipeptides; D010455:Peptides; D011758:Pyrroles; C059571:2-formyl-5-(hydroxymethyl)pyrrole-1-norleucine; D009646:Norleucine; D008239:Lysine; D000409:Alanine