Reaction of Hæmoglobin α^A with Hæmoglobin H

Abstract

TWO hæmoglobin variants which do not contain α-chains are known to occur in vivo, namely, hæmoglobin H (ref. 1), with the composition β^A₄ (ref. 2), and hæmoglobin ‘Bart's’, γ^F₄ (ref. 3). Recently, the in vitro preparation⁴ and properties⁵ of a hæmoglobin consisting of a single α^A-polypeptide chain have been described. Because this in vitro species has an electrophoretic mobility under the usual conditions of analysis which differs from that of hæmoglobin A or of all the known hæmoglobin variants, it was concluded that this hæmoglobin did not occur in vivo. In dissociation and recombination experiments at acid pH, hæmoglobin α^A exchanged with the abnormal α-chains of hæmoglobins I and G/C to form hæmoglobins A and C respectively. It has now been found that, in contrast to these experiments, the reaction of hæmoglobin α^A with hæmoglobin H does not require acid conditions but proceeds rapidly at neutral pH.