Random chemical modification of hemoglobin to identify chloride binding sites in the central dyad axis: their role in control of oxygen affinity.

Knowledge of the mechanism by which chloride and carbon dioxide lower the oxygen affinity of hemoglobin may aid in the design of new blood substitutes since these allosteric regulators permit hemoglobin (Hb) to release its O2. Stable covalent modifiers of hemoglobin, used either in a selective or a random mode, have been used to elucidate the binding sites of CO2 or chloride. For determination of CO2 binding, specific chemical modification of Hb by the carboxymethylation reaction was used. To identify the oxygen-linked chloride binding sites, random chemical modification of Hb was employed.