Oxygen equilibrium of haemoglobin A2 and its variant haemoglobin A2-1 (or B2).

Abstract

EVIDENCE has been presented in a previous investigation1 that the normally occurring minor haemoglobin component A2 has a considerably higher affinity for oxygen than normal Hb–A. The Hb–A2 preparations, which were isolated by carboxymethyl-cellulose (CMC) chromatography2, however, contained relatively large quantities (up to 20 per cent) ferri–Hb or ferri–Hb derivatives. In the work reported here we redetermined, therefore, the oxygen equilibria of normal Hb–A0 and Hb–A2, both being isolated as oxyhaemoglobin without notable oxidation to ferri-haemoglobin derivatives. The abnormal variant of Hb–A2, known as Hb–A21 or Hb–B2 (ref. 3), has also been included in this work.