Kinetic advantage for transport into hamster intestine of glucose generated from phlorizin by brush border beta-glucosidase

Biochim Biophys Acta. 1980 Jul;599(2):652-63. doi: 10.1016/0005-2736(80)90207-2.

Abstract

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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anaerobiosis
  • Animals
  • Biological Transport, Active
  • Cell Membrane / metabolism*
  • Cricetinae
  • Glucose / metabolism*
  • Glucosidases / metabolism*
  • Intestine, Small / metabolism*
  • Kinetics
  • Male
  • Mannitol / metabolism
  • Mesocricetus
  • Microvilli / metabolism*
  • Phlorhizin / metabolism*
  • Tritium
  • beta-Glucosidase / metabolism*

Substances

  • Tritium
  • Mannitol
  • Phlorhizin
  • Glucosidases
  • beta-Glucosidase
  • Glucose