Sedimentation Characteristics of the Human Hæmoglobins A, F and E

Abstract

IT is now well established that normal human hæmoglobin A consists of four polypeptide chains of two types named α and β (ref. 1). The normal foetal hæmoglobin F also consist of four polypeptide chains of two types, namely, α and γ (ref. 2). Thus the difference between the Hb-A and Hb-F is the substitution of two complete γ-chains for the two β-chains. A number of physical and chemical differences between these two hæmoglobins have been discovered³ which are undoubtedly associated with this replacement. However, no systematic study of difference, if any, in the sedimentation character of these two hæmoglobins appears to have been made as most of the previous sedimentation studies were concerned with Hb-A^4–8. This communication describes comparative investigations of the sedimentation behaviour of two normal human hæmoglobins A and F. When the measurements were in progress, samples of pure hæmoglobin E were available from the blood of a homozygous subject (E. E.), whose blood contained 98 per cent Hb-E and 2 per cent Hb-F. Some sedimentation studies were also carried out with this abnormal human hæmoglobin E, which differs from hæmoglobin A by the replacement of a single amino-acid, glutamic acid, by lysine in the 26th residue of the β-chain⁹. No previous sedimentation examination of Hb-E has been carried out.