Premium
Anionic mechanisms of zinc uptake across the human red cell membrane.
Author(s) -
Kalfakakou V,
Simons T J
Publication year - 1990
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1990.sp017957
Subject(s) - dids , chemistry , bicarbonate , zinc , efflux , thiocyanate , ion exchange , inorganic chemistry , band 3 , anion exchanger , ion , membrane , carbonic anhydrase , membrane transport , ion transporter , medicinal chemistry , biophysics , nuclear chemistry , biochemistry , enzyme , erythrocyte membrane , organic chemistry , biology
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.