The oxygen-linked hydrogen ion binding (the Haldane coefficient) of bovine hemoglobin

The Haldane coefficient (the amount of the oxygen-linked hydrogen ion binding of hemoglobin) was determined in bovine erythrolysate (Hb concentration equals 13.5 mM) by means of the differential titration method with varying PCO2 from 0 to 74 mm Hg and pH from 6.0 to 8.5 at 37 degrees C. The maximum value of the coefficient was found to be 0.49 mM per mM Hb at PCO2 equals 0 and pH 7.20. With increasing of PCO2, the coefficient became smaller in all ranges of pH studied. The coefficient under the conditions of pH 7.20 and PCO2 equals 45 mm Hg that are normally prevailing in the interior of bovine erythrocytes was 0.31.