Analysis of the effects of chloride and 2,3-diphosphoglycerate on the cooperative binding of oxygen to hemoglobin.

Analysis of experimental equilibrium constants for the oxygenation of hemoglobin leads to a plausible mechanism for the effect of pH and of chloride ions on cooperativity in hemoglobin. According to this mechanism, the structural changes responsible for cooperativity in chloride- and 2,3-diphosphoglycerate-free hemoglobin are affected only slightly by changes in pH, and the effect of chloride can be accounted for by sequential binding and release of chloride ions during oxygenation.