Kinetic advantage for transport into hamster intestine of glucose generated from phlorizin by brush border beta-glucosidase.
Phlorizin, labeled with tritium only in the glucose moiety, was used as substrate for the beta-glucosidase present in brush border membranes from hamster intestine in order to study, simultaneously, the kinetics of hydrolysis and the fate of the [3H]glucose liberated by the enzyme. The [3H]glucose seems to experience the same hydrolase related transport into the intestinal villi as the hexoses liberated from the common disaccharides byu their respective hydrolases. The released [3H]glucose accumulation rate is only partially inhibited by unlabelled glucose added to the medium as either the free sugar or as the precursors sucrose, lactose or glucose 1-phosphate, and then only when these sugars are present at very high levels. Furthermore, glucose oxidase, added to the medium as a glucose scavenger, has no effect on the uptake rate of the phlorizin hydrolase-liberated sugar. These and other findings are presented as evidence that, under conditions where the Na+-dependent glucose carrier is more than 97% inhibited by phlorizin, the glucose derived from the inhibitor, like the hexoses from disaccharides, has a kinetic advantage for transfer into the intestinal tissue.
D000693:Anaerobiosis; D000818:Animals; D001693:Biological Transport, Active; D002462:Cell Membrane / Q000378:metabolism*; D006224:Cricetinae; D005947:Glucose / Q000378:metabolism*; D005959:Glucosidases / Q000378:metabolism*; D007421:Intestine, Small / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008353:Mannitol / Q000378:metabolism; D008647:Mesocricetus; D008871:Microvilli / Q000378:metabolism*; D010695:Phlorhizin / Q000378:metabolism*; D014316:Tritium; D001617:beta-Glucosidase / Q000378:metabolism*
D014316:Tritium; D008353:Mannitol; D010695:Phlorhizin; D005959:Glucosidases; D001617:beta-Glucosidase; D005947:Glucose