TRANSLATIONAL DIFFUSION OF HEMOGLOBIN IN HUMAN ERYTHROCYTES AND HEMOLYSATES

The translational diffusion coefficient of carboxyhemoglobin was measured in whole human erythrocytes and hemolysates at 25°C under conditions of high-resolution NMR with a magnetic field strength of 9.4 T. Actively shielded z-gradient coils in the Stejskal and Tanner pulsed-magnetic-field-gradient experimental were used; this involved two gradient pulses, of which the second was especially "corrected". The high-resolution character of the spectra ensured ready detection of the envelope of some of the resonances of the hemoglobin-histidyl H2 and H4 protons and thus the determination of the diffusion coefficient from the signal intensities of these protons; the value for a sample of whole cells with a hemoglobin concentration of 355 g (liter cells)-1 was 6.12 ± 1.1 × 10-12 m2s-1 and that for a hemolysate with a hemoglobin concentration of 294 g liter-1 was 1.01 ± 0.06 × 10-11 m2s-1. The cell value of the diffusion coefficient is more than a factor of 10 lower than that of tetrameric hemoglobin A extrapolated to zero concentration. © 1991.