Properties of the Product of Partial Photodissociation of Carbon Monoxide Hemoglobin

Abstract Some properties of the quickly reacting hemoglobin generated by partial photodissociation of human CO hemoglobin have been studied using flash photolysis methods. The absorption spectrum of the rapidly reacting photoproduct is different from that of slowly reacting "normal" hemoglobin and, similarly to other quickly reacting forms, corresponds to that of isolated deoxyhemoglobin chains. The fraction of the fast reacting material increases linearly with the fraction of nonphotodissociated hemoglobin. On the basis of these results and of other information on hemoglobin kinetics it is suggested that this fast reacting species represents partially saturated intermediate which appears transiently when the ligand is suddenly removed from ligand-bound hemoglobin