Shaeffer J R
J Biol Chem. 1980 Mar 25;255(6):2322-4.
A limiting amount of isolated human hemoglobin alpha chains was incubated with a mixture containing excess, but equal, amounts of beta A and beta S chains to form hemoglobin S = alpha 2 beta 2S and hemoglobin = alpha 2 beta 2A, presumably by the reaction 2 alpha + 2 beta leads to 2 alpha beta leads to alpha 2 beta 2. The initial concentration of each type of beta chain was varied from levels (greater than microM) at which the tetrameric form = beta 4 was predominant to levels (less than 1 microM) at which the tetramers had dissociated to monomers. The initial relative concentration of alpha chains remained constant at one-twentieth (0.05) that of total beta chains. About 50% as much hemoglobin S as hemoglobin A was formed in each reaction despite the 500-fold range in the beta chain concentrations among the assays. These results suggest that the difference in amounts of hemoglobins S and A formed was caused by a difference in affinities of individual beta S and beta A chain monomers for alpha chains and not by a difference in the concentrations of beta S and beta A monomers resulting from putative unequal rates of dissociation of beta 4S and beta 4S tetramers.
将有限量的分离出的人血红蛋白α链与一种混合物一起温育，该混合物含有过量但等量的βA链和βS链，以形成血红蛋白S（α2β2S）和血红蛋白A（α2β2A），推测是通过反应2α + 2β→2αβ→α2β2进行的。每种类型的β链的初始浓度从四聚体形式（β4）占主导的水平（大于微摩尔）变化到四聚体已解离为单体的水平（小于1微摩尔）。α链的初始相对浓度保持恒定，为总β链浓度的二十分之一（0.05）。尽管各测定中β链浓度有500倍的范围，但每个反应中形成的血红蛋白S约为血红蛋白A的50%。这些结果表明，血红蛋白S和A形成量的差异是由单个βS链和βA链单体对α链亲和力的差异引起的，而不是由假定的β4S和β4A四聚体解离速率不等导致的βS和βA单体浓度差异引起的。
