Gräslund A, Ehrenberg A, Rupprecht A
Int J Radiat Biol Relat Stud Phys Chem Med. 1977 Feb;31(2):145-52. doi: 10.1080/09553007714550161.
Electron paramagnetic resonance (e.p.r.) was used to study the free radicals induced by gamma-irradiation at 77 K in oriented DNA with incorporated electronaffinic radiosensitizing compounds (4-nitroacetophenone, metronidazole, and Ro-07-0582). The observed e.p.r. spectra were compared with those obtained from pure oriented DNA, which had previously been analysed in detail and found to consist mainly of two components, arising from anion redicals on thymine, and cation radicals on guanine. The major spectral changes caused by the radiosensitizers could be explained as a considerable increase in the formation of cationic free radicals on guanine. There were also indications of the formation of anion radicals on the radiosensitizer molecules. No hydrogen-addition free radicals on thymine were observed when the radiosensitized samples were annealed, in contrast to the pure DNA samples.
利用电子顺磁共振（e.p.r.）研究了在77K下，γ射线辐照掺入亲电子放射增敏化合物（4-硝基苯乙酮、甲硝唑和Ro-07-0582）的定向DNA时所诱导产生的自由基。将观察到的e.p.r.光谱与从纯定向DNA获得的光谱进行比较，之前已对纯定向DNA进行了详细分析，发现其主要由两个成分组成，分别来自胸腺嘧啶上的阴离子自由基和鸟嘌呤上的阳离子自由基。放射增敏剂引起的主要光谱变化可以解释为鸟嘌呤上阳离子自由基形成的显著增加。也有迹象表明放射增敏剂分子上形成了阴离子自由基。与纯DNA样品不同，放射增敏样品退火后未观察到胸腺嘧啶上的氢加成自由基。
