Room-temperature magnetic properties of oxy- and carbonmonoxyhemoglobin

Abstract

The magnetic susceptibility and the density of human HbO2 and HbCO solutions of various concentrations were measured at room temperature, with pure water used as a calibrant. Solutions of unstripped and stripped HbO2 at pH 7.2 in unbuffered water solvent were always less diamagnetic than pure water, whereas solutions of HbCO in identical conditions were always more diamagnetic than pure water. After correcting for concentration-dependent density changes and assuming the HbCO samples to be fully diamagnetic, the paramagnetic reduction of the diamagnetic susceptibility of HbO2 corresponded to a molar susceptibility per heme (.chi. MWheme) of 2460 .+-. 600 .times. 10-8 cgs[centimeter-gram-second]/mol.