title: Anion carrier in the human erythrocyte exists as a dimer.
abstract: The in situ state of assembly of the human erythrocyte anion carrier (band 3) has been investigated by applying target size analysis on the radiation-induced inactivation of anion flux and degradation of polypeptide band 3. Irradiation with a high energy electron beam resulted in inactivation of carrier-mediated anion flux in intact cells, in inside-out vesicles devoid of cytoskeletal and cytoplasmic proteins, and in inside-out vesicles whose band 3 protein has been partially proteolyzed, with little change in leak pathway. The inactivation showed a single exponential function of radiation dose from which the target size of the anion carrier was estimated to be 210,000, 220,000, and 98,000 daltons in intact cells, in the inside-out vesicles, and in the vesicles after a limited proteolysis, respectively. Irradiation also resulted in degradation of the band 3 of the inside-out vesicles, as detected on sodium dodecyl sulfate-gel electrophoresis, with a dose dependence characteristic of a target size of 220,000 daltons. It is suggested that the human erythrocyte anion carrier exists in situ as a dimer of band 3.
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D001457:Anion Exchange Protein 1, Erythrocyte / Q000032:analysis* / Q000528:radiation effects; D002712:Chlorides / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000032:analysis / Q000528:radiation effects; D006801:Humans; D046911:Macromolecular Substances; D008970:Molecular Weight
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte; D002712:Chlorides; D003598:Cytoskeletal Proteins; D046911:Macromolecular Substances; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid