title: Anionic mechanisms of zinc uptake across the human red cell membrane.
abstract: 1. Zinc is taken up into human red cells by two mechanisms that depend upon the presence of anions. One of these requires bicarbonate ions, is inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) and appears to be catalysed by the anion exchanger. The second occurs in the presence of thiocyanate or salicylate ions and may represent transport of a neutral complex with Zn2+. 2. The initial rate of Zn2+ uptake via the anion exchanger is 64 +/- 13 mumol (10(13) cells x h)-1 microM-1 external Zn2+, in the presence of 5 mM-bicarbonate at pH 7.4 and 37 degrees C (+/- S.D.). This is about 1/250 of the corresponding rate of Pb2+ uptake by the anion exchanger. 3. The variation of transport with Zn2+ concentration, HCO3- concentration and pH suggests that the transported species may be ZnCO3Cl- or Zn(HCO3)Cl.OH-. 4. Zinc efflux could not be observed by either of the above routes. This observation suggests that the intracellular free Zn2+ concentration is below 3 nM.
authors.affiliation: Biomedical Sciences Division, King's College London, Strand.
authors.forename: V
authors.initials: V
authors.lastname: Kalfakakou
authors.forename: T J
authors.initials: TJ
authors.lastname: Simons
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000097:blood; D000838:Anions / Q000097:blood*; D001639:Bicarbonates / Q000097:blood; D002413:Cations, Divalent / Q000097:blood; D002414:Cations, Monovalent / Q000097:blood; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006801:Humans; D007854:Lead / Q000097:blood; D012459:Salicylates / Q000097:blood; D020156:Salicylic Acid; D013861:Thiocyanates / Q000097:blood; D015032:Zinc / Q000097:blood*
chemical_list: D000838:Anions; D001639:Bicarbonates; D002413:Cations, Divalent; D002414:Cations, Monovalent; D012459:Salicylates; D013861:Thiocyanates; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D007854:Lead; D015032:Zinc; D020156:Salicylic Acid; C031760:thiocyanate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid