Garner M H, Bogardt R A, Gurd F R
J Biol Chem. 1975 Jun 25;250(12):4398-404.
The rate of reaction between alpha-amino groups and cyanic acid was followed at 26 degrees and ionic strength 0.2 M as a function of pH of human hemoglobin Ao solutions to determine the pK and the pH-independent second order rate constant, kappa, for these groups in the alpha and beta chains. At a given point in time, the extent of the reaction was determined by employing the Beckmann Sequencer as a quantitative tool in which the yields of leucine and histidine in the second Edman degradation cycle were used to define the rates of reaction of the alpha and beta chains, respectively. From these results, the individual were evaluated (Garner, M.H., Garner, W.H., and Gurd, F. R.N. (1973) J. Biol. Chem. 248, 5451-5455). Values for pK for the alpha and beta chains were, respectively, 6.74 and 6.93 for cyanoferrihemoglobin, 6.95 and 7.05 for carboxyhemoglobin, and 7.79 and 6.84 for deoxyhemoglobin. Values for kappa, M- minus 1 S-minus 1, for the alpha and beta chains were, respectively, 12.5 and 17 for cyanoferrihemoglobin, 12 and 18 for carboxyhemoglobin, and 91 and 24 for deoxyhemoglobin. Limits of significance were estimated for both variables in each case. The pK results for valine 1alpha agree well with the value obtained by Hill and Davis (1967) J. Biol. Chem. 242, 2005-2012) for carboxyhemoglobin and with that of Kilmartin and Rossi-Bernardi ((1971) Biochem. J. 124, 31-45) for deoxyhemoglobin. Values obtained for sperm whale myoglobin were 7.77 for pK and 7.4 for kappa. The results are useful for the interpretation of the allosteric interactions of hemoglobin with hydrogen ions, with CO2, and with phosphate.
在26℃和离子强度0.2M的条件下，跟踪α-氨基与氰酸之间的反应速率，该反应速率是人类血红蛋白Ao溶液pH值的函数，以确定α链和β链中这些基团的pK值和与pH无关的二级反应速率常数κ。在给定的时间点，通过使用贝克曼测序仪作为定量工具来确定反应程度，在该工具中，第二个埃德曼降解循环中亮氨酸和组氨酸的产率分别用于定义α链和β链的反应速率。根据这些结果，对个体进行了评估（加纳，M.H.，加纳，W.H.，和古德，F.R.N.（1973年）《生物化学杂志》248，5451 - 5455）。对于氰化高铁血红蛋白，α链和β链的pK值分别为6.74和6.93；对于羧基血红蛋白，分别为6.95和7.05；对于脱氧血红蛋白，分别为7.79和6.84。对于α链和β链，κ的值（M⁻¹S⁻¹）分别为：对于氰化高铁血红蛋白，为12.5和17；对于羧基血红蛋白，为12和18；对于脱氧血红蛋白，为91和24。在每种情况下，都估计了两个变量的显著性极限。缬氨酸1α的pK结果与希尔和戴维斯（1967年）《生物化学杂志》242，2005 - 2012）对羧基血红蛋白获得的值以及基尔马丁和罗西 - 贝尔纳迪（（1971年）《生物化学杂志》124，31 - 45）对脱氧血红蛋白获得的值非常吻合。抹香鲸肌红蛋白获得的值为：pK为7.77，κ为7.4。这些结果有助于解释血红蛋白与氢离子、二氧化碳和磷酸盐之间变构相互作用。
