Benesch R E, Kwong S
Department of Biochemistry and Molecular Biophysics, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA.
J Biol Chem. 1995 Jun 9;270(23):13785-6. doi: 10.1074/jbc.270.23.13785.
Five different human hemoglobins were used to test the postulate that dissociation of hemoglobin (Hb) tetramers into alpha beta dimers and dissociation of heme from globin are linked reactions. Spectrophotometric measurements of the initial rate of heme transfer from Hb to serum albumin were made over a 3000-fold range of Hb concentration and yielded the heme-globin dissociation rate constant for tetramers and that for dimers. The tetramer-dimer dissociation constant (K4,2) could then be calculated from the rate constant at intermediate concentrations. The values obtained for the five hemoglobins, spanning a 250-fold range in K4,2, were in good agreement with those found by direct methods. The relation between this new linkage reaction of hemoglobin and the classical ones, such as the reciprocal relation between the binding of oxygen and protons, is discussed briefly.
使用了五种不同的人类血红蛋白来检验血红蛋白（Hb）四聚体解离为αβ二聚体以及血红素与珠蛋白解离是相关联反应这一假设。在血红蛋白浓度跨越3000倍的范围内，通过分光光度法测量了血红素从血红蛋白向血清白蛋白转移的初始速率，得出了四聚体和二聚体的血红素 - 珠蛋白解离速率常数。然后可以根据中间浓度下的速率常数计算四聚体 - 二聚体解离常数（K4,2）。所获得的五种血红蛋白的值，其K4,2范围跨越250倍，与通过直接方法得到的值高度一致。本文简要讨论了血红蛋白这种新的关联反应与经典反应（如氧与质子结合的倒数关系）之间的联系。
