English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Inhibition of inorganic anion transport across the human red blood cell membrane by chloride-dependent association of dipyridamole with a stilbene disulfonate binding site on the band 3 protein

Legrum, B., & Passow, H. (1989). Inhibition of inorganic anion transport across the human red blood cell membrane by chloride-dependent association of dipyridamole with a stilbene disulfonate binding site on the band 3 protein. Biochimica et Biophysica Acta-Biomembranes, 979(2), 193-207. doi:10.1016/0005-2736(89)90435-5.

Item is

Basic

show hide
Genre: Journal Article

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Legrum, Barbara1, Author           
Passow, Hermann1, Author           
Affiliations:
1Department of Cell Physiology, Max Planck Institute of Biophysics, Max Planck Society, ou_3264817              

Content

show
hide
Free keywords: Anion transport; Erythrocyte; Dipyridamole; Band 3 protein
 Abstract: The inhibition of inorganic anion transport by dipyridamole (2,6-bis(diethanolamino)-4,8-dipiperidinopyrimido[5,4-d] pyrimidine) takes place only in the presence of Cl-, other halides, nitrate or bicarbonate. At any given dipyridamole concentration, the anion flux relative to the flux in the absence of dipyridamole follows the equation: Jrel = (1 + alpha 2[Cl-])/(1 + alpha 4[Cl-]) where alpha 2 and alpha 4 are independent of [Cl-] but dependent on dipyridamole concentration. At high [Cl-] the flux approaches alpha2/alpha4, which decreases with increasing dipyridamole concentration. Even when both [Cl-] and dipyridamole concentration assume large values, a small residual flux remains. The equation can be deduced on the assumption that Cl- binding allosterically increases the affinity for dipyridamole binding to band 3 and that the bound dipyridamole produces a non-competitive inhibition of sulfate transport. The mass-law constants for the binding of Cl- and dipyridamole to their respective-binding sites are about 24 mM and 1.5 microM, respectively (pH 6.9, 26 degrees C). Dipyridamole binding leads to a displacement of 4,4'-dibenzoylstilbene-2,2'-disulfonate (DBDS) from the stilbenedisulfonate binding site of band 3. The effect can be predicted quantitatively on the assumption that the Cl- -promoted dipyridamole binding leads to a competitive replacement of the stilbenedisulfonates. For the calculations, the same mass-law constants for binding of Cl- and dipyridamole can be used that were derived from the kinetic studies on Cl- -promoted anion transport inhibition. The newly described Cl- binding site is highly selective with respect to Cl- and other monovalent anion species. There is little competition with SO42-, indicating that Cl- binding involves other than purely electrostative forces. The affinity of the binding site to Cl- does not change over the pH range 6.0-7.5. Dipyridamole binds only in its deprotonated state. Binding of the deprotonated dipyridamole is pH-independent over the same range as Cl- binding.

Details

show
hide
Language(s): eng - English
 Dates: 1988-09-272003-03-311989-02-27
 Publication Status: Published in print
 Pages: 15
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1016/0005-2736(89)90435-5
PMID: 2923878
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Biochimica et Biophysica Acta-Biomembranes
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Amsterdam : Elsevier
Pages: - Volume / Issue: 979 (2) Sequence Number: - Start / End Page: 193 - 207 Identifier: ISSN: 0005-2736
CoNE: https://pure.mpg.de/cone/journals/resource/954926938702