Solubilization of hemoglobin S by other hemoglobins.

Abstract
The polymerization of mixtures of [human] Hb S with hemoglobins A, A2 and F was investigated by analysis of the proportions of S and non-S Hb both in the supernate and in the pellet after centrifugation. In all cases, the non-S Hb was incorporated into the polymer even in the absence of hybrids in the order A > A2 > F. The solubility of Hb S is substantially increased by the other hemoglobins, especially by Hb F, which would account for its antisickling effect. The excluded volume effect of the other Hb on Hb S is largely counterbalanced by the solubilizing effect arising from the interaction between the 2 Hb in solution. The ability of hybrid Hb to gel was demonstrated directly with tetramers in which .alpha..beta.s dimers were covalently linked to .alpha..beta.A, .alpha..delta.A2 and .alpha..gamma.F dimers.