Hot atom labeling of myoglobin and hemoglobin and biophysical studies of oxygen and carbon monoxide binding to carp hemoglobin

uman Hb, the monomeric Hb of Glycera dibranchiata and horse Mb were modified by replacement of the protoheme with 2,4-dibromodeuteroheme. Following neutron capture by ;Carp Hb's containing proto-, meso-, deutero- and dibromoheme were prepared. Kinetic and thermodynamic parameters for oxygen and CO binding were determined at Ph 6 (+IHP) (T-state, low-affinity protein) and Ph 9 (R-state, high-affinity protein). Parameters for the binding of oxygen and CO were related to the properties of the four hemes to estimate the inductive and steric factors in the ligation process. Our results suggest that the steric factors are more important for the T-state than for the R-state. The T-state carp Hbs were very readily oxidized. Two new procedures were developed for the rapid determination of oxygen equilibrium isotherms for the T-state carp Hbs.;The kinetic and thermodynamic parameters for ligation of oxygen and CO with the isolated carp...