The high Km glucose transporter of islets of Langerhans is functionally similar to the low affinity transporter of liver and has an identical primary sequence.

Détails

ID Serval
serval:BIB_F1226B647A19
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
The high Km glucose transporter of islets of Langerhans is functionally similar to the low affinity transporter of liver and has an identical primary sequence.
Périodique
Journal of Biological Chemistry
Auteur(s)
Johnson J.H., Newgard C.B., Milburn J.L., Lodish H.F., Thorens B.
ISSN
0021-9258
Statut éditorial
Publié
Date de publication
04/1990
Peer-reviewed
Oui
Volume
265
Numéro
12
Pages
6548-6551
Langue
anglais
Notes
Publication types: Comparative Study ; Journal Article
Résumé
The liver has been shown to contain a facilitated diffusion glucose transporter with high Km for glucose that is structurally distinct from the low Km glucose transporters found in most other tissues. We find that 3-O-methyl glucose is greater than 90% equilibrated across dispersed islet cells within 60 s, consistent with a facilitated diffusion transport mechanism. L-Glucose uptake was minimal throughout the time course, indicating stereospecificity. Measurement of glucose transport over a range of 3-O-methyl glucose concentrations from 0.05 to 60 mM revealed the presence of a component of glucose transport with an apparent Km of 17 mM, a value essentially identical to that previously reported for liver. Interestingly, a second component of glucose transport was also observed with an apparent Km of 1.4 mM, as has been reported for other tissues such as erythrocytes that are known to contain the "HepG2" or "erythroid/brain" type glucose transporter. Further evidence for the existence of two transport components is provided by the observation that a low concentration of cytochalasin B (0.4 microM) completely inhibits the low Km transport activity but has no effect on the high Km transporter. The kinetic similarity of high Km glucose transport in liver and islets is readily understood in light of our structural analysis. Sequence analysis of cDNA clones indicates that the liver and islet glucose transporters have identical sequences and, thus, are the products of the same gene.
Mots-clé
3-O-Methylglucose, Amino Acid Sequence, Animals, Cloning, Molecular, Cytochalasin B/pharmacology, DNA/genetics, Escherichia coli/genetics, Gene Library, Islets of Langerhans/metabolism, Kinetics, Liver/metabolism, Methylglucosides/metabolism, Monosaccharide Transport Proteins/genetics, Monosaccharide Transport Proteins/metabolism, Nucleic Acid Hybridization, Polymerase Chain Reaction, Rats, Urea/metabolism
Pubmed
Web of science
Création de la notice
24/01/2008 14:41
Dernière modification de la notice
03/03/2018 22:38
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