Abstract
The role of a transmembrane Ca2+ gradient in anion transport by Band 3 of human resealed erythrocyte ghosts has been studied. The results show that a transmembrane Ca2+ gradient is essential for the conformation of erythrocyte Band 3 with higher anion transport activity. The dissipation of the transmembrane Ca2+ gradient by the ionophore A23187 inhibits the anion transport activity. The extent of this inhibition approaches 90% as the Ca2+ concentration on both sides of the ghost membrane is increased to 1.0mM and half-maximum inhibition is observed at 0.25mM Ca2+ Addition of ATP (0.4mM) to the resealing medium can partly reestablish the transmembrane Ca2+ gradient by activation of Ca2+-ATPase and alleviate the inhibition to some extent. N-ethylmaleimide, an inhibitor of erythrocyte Ca2+-ATPase, prevents such restoration. Electron micrographs reveal that numerous larger intramembranous particles can be observed on the P-faces of freeze-fractured resealed ghosts in the absence of a transmembrane Ca2+ gradient.
Original language | English (US) |
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Pages (from-to) | 299-311 |
Number of pages | 13 |
Journal | Bioscience Reports |
Volume | 16 |
Issue number | 4 |
DOIs | |
State | Published - 1996 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology