Pulsed field gradient nmr determination of the temperature dependence of the tracer diffusion coefficient of hemoglobin

We have studied the temperature dependence of the tracer diffusion coefficient of carbonmonoxy hemoglobin A (HbA‐CO) by means of pulsed‐field gradient nmr (PFG‐nmr). Measurements were made over the temperature range from 15 to 35°C for samples having concentrations 7.4 and 16.7 g/dL. No significant deviations were found from the predictions of the Stokes‐Einstein relation. Thus, this work does not corroborate the recently proposed conformational change in hemoglobin at 22°C. The advantages of PFG‐nmr for the study of hemoglobin are discussed.