Reaction of haemoglobin αA with haemoglobins βA4, γF4 and δA2

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Abstract
The rate of reaction of hemoglobin-[alpha]A (Hb-[alpha]) with Hb-[beta]4, Hb- [gamma] 4 and Hb-[delta] at neutral pH to form new hemoglobin species that are electrophoretically indistinguishable from Hb-A, Hb-F and Hb-A2 respectively has been examined over the termperature range 0-37[degree] by quantitative starch-gel electrophoresis. The rate of formation of "Hb-A" in mixtures of Hb-[alpha] and Hb-[beta]4 was approximately 3 times as great at 37[degree] as at 25[degree], and 20-30 times as great as at 0[degree]. In mixtures of Hb-[alpha] with Hb-[beta]4 in which stored samples of Hb-[beta]4 were used the rate of formation of "Hb-A" was significantly slower. At 0[degree] the rate of formation of "Hb-F" from Hb-[alpha] and Hb- [gamma] 4 was negligible, but was appreciable at 25[degree] and approximately twice as fast as 37[degree]. At corresponding temperatures the formation of "Hb-F" in Hb-[alpha]/Hb-[gamma] 4 mixtures was approximately tenfold slower than the formation of "Hb-A" in Hb-[alpha]/Hb-[beta]4 mixtures. These findings in-vitro are used to explain the situation in-vivo in Hb-H disease, in which there appears to be a deficiency of [alpha]-chain synthesis and the observed compositions of hemolysates may be accounted for in terms of competition between [beta]- and [gamma]-chains for the available [alpha] - chains.