Kinetic properties of cobalt--iron hybrid hemoglobins

The replacement of O2 with CO was studied on cobalt-iron hemoglobin hybrids. Both proto- and mesocobalt hemes were used for the reconstitution. In the oxy quaternary conformation no difference is observed between alpha- and beta-subunits when only proto hemes are present in the hybrid (k4 = 30 s-1, k'4/l'4 = 2.5). If Co-meso heme is present on the beta-chains the binding properties of the partner subunit are modified (k'4/l'4 = 4).