Nagai M, Yubisui T, Yoneyama Y
J Biol Chem. 1980 May 25;255(10):4599-602.
Enzymatic reduction of the hemoglobin (Hb) M group was studied. Hb M Milwaukee-1 and Hb M Saskatoon were reduced by NADH-cytochrome b5 reductase highly purified from human erythrocytes. Hb M Saskatoon was also reduced by another enzyme in red cells, NADPH-flavin reductase. The reduction rates of Hb M Saskatoon by both enzymes were almost the same as those of MetHb A. The reduction of Hb M Milwaukee-1 by NADH-cytochrome b5 reductase progressed much more slowly than that of Hb M Saskatoon and MetHb A. It took 1/2 h and 10 h for the 50% reduction of Hb M Saskatoon and Hb M Milwaukee-1, respectively. These two methemoglobin reductases from erythrocytes did not reduce other hemoglobins M such as Hb M Iwate, Hb M Boston, or Hb M Hyde Park. A possible role of these abnormal hemoglobins as oxygen carriers and the reason for cyanosis in the patients of Hb M Saskatoon and Hb M Milwaukee-1 are discussed.
研究了血红蛋白（Hb）M组的酶促还原作用。从人红细胞中高度纯化得到的NADH - 细胞色素b5还原酶可使Hb M密尔沃基 - 1和Hb M萨斯卡通还原。红细胞中的另一种酶NADPH - 黄素还原酶也可使Hb M萨斯卡通还原。两种酶对Hb M萨斯卡通的还原速率与高铁血红蛋白A（MetHb A）的还原速率几乎相同。NADH - 细胞色素b5还原酶对Hb M密尔沃基 - 1的还原进展比Hb M萨斯卡通和MetHb A慢得多。Hb M萨斯卡通和Hb M密尔沃基 - 1分别达到50%还原所需时间为半小时和10小时。红细胞中的这两种高铁血红蛋白还原酶不能还原其他血红蛋白M，如Hb M岩手、Hb M波士顿或Hb M海德公园。讨论了这些异常血红蛋白作为氧载体的可能作用以及Hb M萨斯卡通和Hb M密尔沃基 - 1患者出现发绀的原因。
