Bunn H F, Haney D N, Kamin S, Gabbay K H, Gallop P M
J Clin Invest. 1976 Jun;57(6):1652-9. doi: 10.1172/JCI108436.
Hemoglobin A1c, the most abundant minor hemoglobin component in human erythrocytes, is formed by the condensation of glucose with the N-terminal amino groups of the beta-chains of Hb A. The biosynthesis of this glycosylated hemoglobin was studied in vitro by incubating suspensions of reticulocytes and bone marrow cells with [3H]leucine or 59Fe-bound transferrin. In all experiments, the specific activity of Hb A1c was significantly lower than that of Hb A, suggesting that the formation of Hb A1c is a posttranslational modification. The formation of Hb A1c in vivo was determined in two individuals who were given an infusion of 59Fe-labeled transferrin. As expected, the specific activity of Hb A rose promptly to a maximum during the 1st week and remained nearly constant thereafter. In contrast, the specific activity of Hb A1c and also of Hbs A1a and A1b rose slowly, reaching that of Hb A by about day 60. These results indicate that Hb A1c is slowly formed during the 120-day life-span of the erythrocyte, probably by a nonenzymatic process. Patients with shortened erythrocyte life-span due to hemolysis had markedly decreased levels of Hb A1c.
糖化血红蛋白A1c是人类红细胞中含量最丰富的次要血红蛋白成分，它由葡萄糖与血红蛋白A（Hb A）β链的N端氨基缩合而成。通过用[3H]亮氨酸或59Fe结合的转铁蛋白孵育网织红细胞和骨髓细胞悬液，在体外研究了这种糖基化血红蛋白的生物合成。在所有实验中，Hb A1c的比活性显著低于Hb A，这表明Hb A1c的形成是一种翻译后修饰。在两名输注59Fe标记转铁蛋白的个体中测定了体内Hb A1c的形成。正如预期的那样，Hb A的比活性在第1周迅速升至最高并在此后保持几乎恒定。相比之下，Hb A1c以及Hb A1a和A1b的比活性上升缓慢，在大约第60天时达到Hb A的比活性。这些结果表明，Hb A1c在红细胞120天的寿命期间缓慢形成，可能是通过非酶促过程。由于溶血导致红细胞寿命缩短的患者，其Hb A1c水平明显降低。
