Thelander L, Gräslund A, Thelander M
Biochem Biophys Res Commun. 1983 Feb 10;110(3):859-65. doi: 10.1016/0006-291x(83)91040-9.
A radical-free preparation of a highly purified ribonucleotide reductase from calf thymus was shown to generate an M2-specific tyrosine free radical on incubation with iron and dithiothreitol in the presence of air. The radical is essential for activity but once formed has a half-life of about 10 min. Using the calf thymus enzyme, there is a continual requirement of oxygen and iron for ribonucleotide reduction indicating a continual regeneration of the radical during enzyme catalysis. We therefore propose that one way a cell may regulate ribonucleotide reductase activity is by controlling the generation of M2-specific tyrosine free radicals within existing M2 molecules.
从小牛胸腺中制备的一种高度纯化的无自由基核糖核苷酸还原酶，在空气存在下与铁和二硫苏糖醇一起孵育时，会产生一种M2特异性酪氨酸自由基。该自由基对活性至关重要，但一旦形成，半衰期约为10分钟。使用小牛胸腺酶时，核糖核苷酸还原持续需要氧气和铁，这表明在酶催化过程中自由基会持续再生。因此，我们提出细胞调节核糖核苷酸还原酶活性的一种方式可能是通过控制现有M2分子内M2特异性酪氨酸自由基的产生。
