Laser-induced time-resolved photoacoustic calorimetry study on photo-dissociation of human and bovine oxyhemoglobin.

The dynamics of the enthalpy and volume changes related to the photo-dissociation of oxygen from human and bovine oxyhemoglobin are investigated by nanosecond time-resolved photoacoustic calorimetry (PAC). The values of enthalpy and volume change associated with the above process are deltaH = 37.8 +/- 3 kcal/mol, deltaV = 5.0 +/- 1 ml/mol for human HbO(2); and deltaH = 35.7 +/- 3.5 kcal/mol, deltaV = 4.8 +/- 1 ml/mol for bovine HbO(2), respectively. A possible explanation for the similar values between both human and bovine oxyhemoglobin is proposed. In addition, the PAC results for human HbO(2) and HbCO are compared and discussed.