Kinetic Investigation of Haemoglobin Bohr Effect by Flash Photolysis

Abstract

THE Bohr effect, perhaps the first of the important linked functions of haemoglobin to be noted¹, describes the relationship between pH and the ligand affinity of haemoglobin and the converse effect of percentage saturation on the affinity of the protein molecule for protons. The nature of the amino-acid residues responsible for the Bohr effect has been the subject of some speculation^2,3. Recently they were identified by Kilmartin and Rossi-Bernardi⁴ and by Perutz et al.⁵, who presented convincing evidence that at least 75 per cent of the alkaline Bohr effect arises because of pK shifts induced by the interaction between the ammo termini and the carboxyl terminal arginines of complementary α-chains as well as between aspartic acid β94 and histidine β146 of the same chain.