Inhibition of phosphate transport across the human erythrocyte membrane by chemical modification of sulfhydryl groups.
Effects of sulfhydryl-reactive reagents on phosphate transport across human erythrocyte membranes were examined using 31P NMR. Phosphate transport was significantly inhibited in erythrocytes treated with sulfhydryl modifiers such as N-ethylmaleimide, diamide, and Cu2+/o-phenanthroline. Quantitation of sulfhydryl groups in band 3 showed that the inhibition is closely associated with the decrease of sulfhydryl groups. Data from erythrocytes treated with diamide or Cu2+/o-phenanthroline demonstrated that intermolecular cross-linking of band 3 by oxidation of a sulfhydryl group, perhaps Cys-201 or Cys-317, decreases the phosphate influx by about 10%. The inhibition was reversed by reduction using dithiothreitol. These results suggest that sulfhydryl groups in the cytoplasmic domain of band 3 may play an important role in the regulation of anion exchange across the membrane.
Yamaguchi
T
T
Department of Chemistry, Faculty of Science, Fukuoka University, Japan.
Kimoto
E
E
D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry; D001692:Biological Transport / Q000187:drug effects; D002413:Cations, Divalent; D003300:Copper / Q000737:chemistry; D003958:Diamide / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005033:Ethylmaleimide / Q000737:chemistry; D006801:Humans; D007700:Kinetics; D010618:Phenanthrolines / Q000737:chemistry; D010759:Phosphorus Isotopes; D013438:Sulfhydryl Compounds / Q000737:chemistry* / Q000494:pharmacology
D001457:Anion Exchange Protein 1, Erythrocyte; D002413:Cations, Divalent; D010618:Phenanthrolines; D010759:Phosphorus Isotopes; D013438:Sulfhydryl Compounds; D003958:Diamide; D003300:Copper; D005033:Ethylmaleimide; C025205:1,10-phenanthroline