Na(+)-dependent transport of aminopeptidase-resistant sugar-coupled tripeptides in rat intestine.
Aminopeptidase-degradable tripeptide, tyrosylglycylglycine (TGG, a part of aminopeptidase-degradable enkephalines), was coupled with sugars (cellobiose, maltose, lactose, gentiobiose and glucose). These sugar-coupled TGGs were stable enough to be transported from the mucosal to the serosal side in rat everted small intestine, while TGG was not stable enough to be transported. The transport of sugar-coupled TGGs was decreased in the absence of Na+, indicating the Na(+)-dependent transport of sugar-coupled TGG in rat intestine. Cellobiose-coupled TGG and glucose-coupled TGG did not mutually inhibit their transport. It was suggested that the intestinal Na(+)-dependent transporter for disaccharide-coupled tripeptides, which have a pyranose ring, was different from that of monosaccharide-coupled tripeptide, which has no pyranose ring.
Mizuma
T
T
Department of Biopharmaceutics, Tokyo College of Pharmacy, Japan.
Sakai
N
N
Awazu
S
S
D000595:Amino Acid Sequence; D000818:Animals; D006020:Glycopeptides / Q000138:chemical synthesis / Q000378:metabolism*; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D007408:Intestinal Absorption / Q000187:drug effects*; D007583:Jejunum / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000494:pharmacology*
D006020:Glycopeptides; D007202:Indicators and Reagents; D009842:Oligopeptides; C044757:tyrosyl-glycyl-glycine; D012964:Sodium