The effect of mercaptoethanol and urea on the molecular weight of hemoglobin

Abstract 1. 1. Unlike horse hemoglobin, human hemoglobin is not dissociated by concentrated urea, although its shape is considerably altered. 2. 2. Horse and human hemoglobins are equally dissociated by mercaptoethanol, and even further, but still equally, by a combination of mercaptoethanol and urea. 3. 3. The mechanism of mercaptoethanol action is not clear, but the data suggest that it attacks bonds other than those sensitive to urea. 4. 4. Sedimentation-diffusion measurements, in this study, indicate that dissociation of horse hemoglobin by concentrated urea is less complete than that found in previous reports. An explanation in terms of heterogeneity and a rapid dissociation-association equilibrium is suggested.