Electrogenic Nature of Rat Sodium-Dependent Multivitamin Transport
| Autor: | Haiping Wang, Frederick H. Leibach, Vadivel Ganapathy, Lawrence D. Devoe, Puttur D. Prasad, Sonne R. Srinivas |
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| Rok vydání: | 2000 |
| Předmět: |
Biophysics
Biological Transport Active Biotin Transfection Biochemistry Pantothenic Acid Membrane Potentials Xenopus laevis chemistry.chemical_compound medicine Animals Molecular Biology Membrane Glycoproteins Symporters Cell Membrane Sodium Substrate (chemistry) Transporter Cell Biology Oocyte Recombinant Proteins Rats Kinetics Biotin transport Membrane medicine.anatomical_structure chemistry Barium Permeability (electromagnetism) COS Cells Oocytes Potassium Female Carrier Proteins Multivitamin |
| Zdroj: | Biochemical and Biophysical Research Communications. 270:836-840 |
| ISSN: | 0006-291X |
| DOI: | 10.1006/bbrc.2000.2498 |
| Popis: | We report on the electrogenic nature of the transport process mediated by the rat sodium-dependent multivitamin transporter. In Cos-7 cells, the relationship of Na+ concentration versus biotin and pantothenate uptake rate was sigmoidal with a Na+:substrate stoichiometry of 2:1. In Cos-7 cells expressing rat SMVT biotin transport was significantly higher when the membrane was hyperpolarized and considerably reduced when the membrane was depolarized. Similarly, biotin uptake in X. laevis oocytes expressing rat SMVT was inhibited with depolarized oocyte membrane by altering the K+ permeability across the membrane. It is concluded that the transport of biotin and pantothenate mediated by rat SMVT is electrogenic with a Na+:substrate coupling ratio of 2:1 and that the transport process is associated with the transfer of one net positive charge across the membrane per transport cycle. |
| Databáze: | OpenAIRE |
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