ABSTRACT
The packaging of hemoglobin in the human erythrocyte has advantages that include stabilization of the hemoglobin molecule, modification of its oxygen dissociation, and protection from oxidation [1]. There are consequences, however, of keeping hemoglobin within a cell membrane. The osmotic gradient created by separating hemoglobin from the plasma drives water into the cell, and the electrical gradient established by the “fixed anions” of hemoglobin creates Donnan forces that also lead to an increase in cell water [2]. The red blood cell must compensate for these hemoglobin-induced gains in cell water or hemolysis will occur. This is done by creating a disequilibrium of the permeant cations Na and K [3]. A great number of studies have defined ion transport processes important in establishing and maintaining this cation disequilibrium in red cells.
