Electron spin resonance studies on the inorganic-anion-transport system of the human red blood cell. Binding of a disulfonatostilbene spin label (NDS-TEMPO) and inhibition of anion transport.

K F Schnell, W Elbe, J Käsbauer, E Kaufmann

Biochimica et biophysica acta 1983 Jul 13

filter terms:

The disulfonatostilbene spin label, NDS-TEMPO, was synthesized (purity over 96%) and the binding of the spin label to human red-cell ghosts was studied. NDS-TEMPO is readily absorbed to the membrane surface. Both pretreatment of the ghosts with FDNB and DIDS and the presence of DNDS completely prevent the binding of NDS-TEMPO to red-cell ghosts. Chloride and sulfate competitively inhibit the binding of NDS-TEMPO. Conversely, NDS-TEMPO is a strong, competitive inhibitor of chloride and of sulfate transport. The dissociation constants of NDS-TEMPO from the ESR studies were in the range 1.0-2.0 microM (pH 7.6, 20 degrees C). The inhibition constants of NDS-TEMPO as obtained from the flux experiments were in the range 0.5-2.5 microM (pH 7.3, 25 degrees C). The close accordance of the NDS-TEMPO dissociation constants from the ESR studies with the NDS-TEMPO inhibition constants from the flux measurements indicate a specific labeling of the inorganic-anion-transport system.

Citation

K F Schnell, W Elbe, J Käsbauer, E Kaufmann. Electron spin resonance studies on the inorganic-anion-transport system of the human red blood cell. Binding of a disulfonatostilbene spin label (NDS-TEMPO) and inhibition of anion transport. Biochimica et biophysica acta. 1983 Jul 13;732(1):266-75