Quantum Yields in Photolyses of Mammalian Carboxy-Hemoglobin Studied by Pulsed Laser Pump-Probe Technique

The mechanisms describing the cooperative binding of CO or other ligands to hemoglobins (Hb) has been widely studied as an important fundamental problem for a long time. In this paper, the quantum yields in photolyses of carboxy-hemoglobins (HbCO) of mammals, such as human, pig, bovine, horse and rabbit, are investigated by the optical pump-probe technique. In the technique, the HbCO of the mammals are irradiated by a pulsed laser beam, and then the HbCO is photo-dissociated. Another continuous optical beam is used as a probe beam to detect the absorbance change induced by the photo-dissociation of the HbCO. The measured results show that the photolysis quantum yields of the HbCO are different for varies mammals, among them the quantum yields for porcine, bovine and equine HbCO are very close, but for the HbCO of rabbit, which is much smaller than the others. Finally, the results are analyzed and discussed.