Abstract.
K-Cl cotransport is abnormally active in erythrocytes containing positively charged hemoglobins such as Hb S (SS: β6 Glu → Val) or Hb C (CC: β6 Glu → Lys). The relatively younger age of erythrocytes in these diseases cannot completely account for the increased K-Cl cotransport activity. It has been suggested that these positively charged Hb may interact with the K-Cl cotransport system or one of its regulators and induce changes in its functional activity. We report here data on the volume- and pH-dependence of K-Cl cotransport in ghosts obtained from normal and sickle erythrocytes, and on the effect of addition of either Hb A or Hb S before resealing. In erythrocyte ghosts prepared with the gel column method to contain minimal amounts of Hb, (white ghosts, WG), K-Cl cotransport has similar magnitude in normal and sickle erythrocytes, is not inhibited by alkaline pH and it is volume-independent. Addition of low concentrations of Hb A to WG from normal erythrocytes decreases the magnitude of K-Cl cotransport and restores its volume dependency, but not its pH sensitivity. Addition of Hb S to WG from either normal or sickle erythrocytes restores the volume-dependent component of K-Cl cotransport and increases the magnitude of flux mediated by this transporter. Thus, Hb A and Hb S seem to affect in different manners the functional properties of K-Cl cotransport.
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Received: 29 May 1998/Revised: 3 November 1998
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Vitoux, D., Beuzard, Y. & Brugnara, C. The Effect of Hemoglobin A and S on the Volume- and pH-Dependence of K-Cl Cotransport in Human Erythrocyte Ghosts. J. Membrane Biol. 167, 233–240 (1999). https://doi.org/10.1007/s002329900487
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DOI: https://doi.org/10.1007/s002329900487