Oxygen Equilibria of Hemoglobin A2 and Hemoglobin Lepore*

Abstract

The oxygen equilibria of hemoglobins A, Lepore, and A2 isolated by zone electrophoresis were studied. The oxygen equilibrium of hemoglobin A2 did not differ significantly from that of hemoglobin A subjected to the same experimental conditions. A significant increase in oxygen affinity was demonstrated in isolated hemoglobin Lepore as compared with isolated hemoglobin A. The expected and observed effect of this increased affinity on unfrac-tionated hemoglobin from a Lepore heterozygote was so slight as to be within experimental error. Isolated hemoglobins A, A2, and Lepore appeared to have the same heme-heme interaction and each exhibited a Bohr effect, although the Bohr effect of hemoglobin Lepore might have differed from that of hemoglobin A. The increased oxygen affinity of hemoglobin Lepore may be an effect of altered interchain relationships resulting from the presence of the unusual non-alpha chains in the tetramer.