Deeble D J, von Sonntag C
Int J Radiat Biol Relat Stud Phys Chem Med. 1987 May;51(5):791-6. doi: 10.1080/09553008714551081.
The reactions of the electron adducts of thymine, uracil and 1,3-dimethylthymine in the presence of phosphate buffer and low oxygen concentrations have been investigated. Oxygen reacts with the pyrimidine electron adducts and their O(4)-protonated forms to restore the pyrimidine and produce O2-./HO2.. Thus oxygen acts as a radiation protector. In the presence of high buffer concentrations the electron adducts are irreversibly protonated at C(6). On reaction of this radical with oxygen no restitution of the original pyrimidine occurs and the pyrimidine is destroyed. Thus phosphate buffer acts as a radiation sensitizer. Some speculations are made as to the possible relevance of these reactions to biological systems.
研究了胸腺嘧啶、尿嘧啶和1,3 - 二甲基胸腺嘧啶的电子加合物在磷酸盐缓冲液和低氧浓度存在下的反应。氧气与嘧啶电子加合物及其O(4)-质子化形式反应，使嘧啶恢复并产生O2-./HO2..。因此，氧气起到辐射防护剂的作用。在高缓冲液浓度存在下，电子加合物在C(6)处不可逆地质子化。该自由基与氧气反应时，不会使原来的嘧啶恢复，嘧啶被破坏。因此，磷酸盐缓冲液起到辐射增敏剂的作用。对这些反应与生物系统可能的相关性进行了一些推测。
