Nagai M, Yoneyama Y
J Biol Chem. 1983 Dec 10;258(23):14379-84.
The reduction of hemoglobins (Hb) M such as Hb M Iwate, Hb M Boston, Hb M Hyde Park, Hb M Saskatoon, and Hb M Milwaukee by the ferredoxin and ferredoxin-NADP reductase system was studied systematically under anaerobic conditions. The enzyme system could not reduce the abnormal chains in methemoglobin M with an alpha chain anomaly but effectively converted the methemoglobin M with a beta chain anomaly to the fully reduced form. During the reduction of the methemoglobin M with a beta chain anomaly, the spectra showed a shift of the initial isosbestic points, indicating the possible formation of intermediate hemoglobins in the partially reduced state. On the reduction mode of the methemoglobin M, however, it was classified into three types. 1) Only normal chains were reduced (Hb M Iwate and Hb M Boston). 2) Sequential reduction from normal to abnormal chains occurred (Hb M Milwaukee and Hb M Hyde Park). 3) Normal chains were preferentially reduced, but the reduction of abnormal chains also started at the same rate when the reduction of normal ones had proceeded halfway (Hb M Saskatoon). These differences are discussed in relation to the redox potential of each abnormal chain in methemoglobin M.
在厌氧条件下，系统研究了铁氧化还原蛋白和铁氧化还原蛋白 - NADP还原酶系统对诸如血红蛋白（Hb）M岩手、Hb M波士顿、Hb M海德公园、Hb M萨斯卡通和Hb M密尔沃基等血红蛋白M的还原作用。该酶系统不能还原具有α链异常的高铁血红蛋白M中的异常链，但能有效地将具有β链异常的高铁血红蛋白M转化为完全还原形式。在还原具有β链异常的高铁血红蛋白M的过程中，光谱显示初始等吸收点发生了移动，表明在部分还原状态下可能形成了中间血红蛋白。然而，关于高铁血红蛋白M的还原模式，可分为三种类型。1）仅正常链被还原（Hb M岩手和Hb M波士顿）。2）从正常链到异常链依次发生还原（Hb M密尔沃基和Hb M海德公园）。3）正常链优先被还原，但当正常链的还原进行到一半时，异常链的还原也以相同速率开始（Hb M萨斯卡通）。结合高铁血红蛋白M中各异常链的氧化还原电位对这些差异进行了讨论。
