Total Dissociation of Horse Hæmoglobin

Abstract

THE native hæmoglobin of the horse, in unbuffered dilute salt solutions at the isoelectric point, is totally dissociated into molecules of half the normal molecular weight, when high concentrations of urea (more than 4 M), acetamide (6.5 M), or formamide (3 M) are present in the solution. The sedimentation constant, measured in the Svedberg ultraeentrifuge and corrected to its equivalent in pure water at 20°, falls from 4.5 to 3.1 × 10¹³, and the diffusion constant, measured by the refractometric method of Lamm and Polson¹, rises to 7.8 × 10⁷, the value characteristic of ovalbumen. The partial specific volume is not appreciably changed.