Methylperoxyl radicals as intermediates in the damage to DNA irradiated in aqueous dimethyl sulfoxide with gamma rays
Methylperoxyl radicals as intermediates in the damage to DNA irradiated in aqueous dimethyl sulfoxide with gamma rays
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DOI：
10.2307/3579305
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发表时间：
1996-10-01
影响因子：
3.4
通讯作者：
Cunningham, RP
中科院分区：
文献类型：
--
作者：
Milligan, JR;Ng, JYY;Cunningham, RP
我们用琼脂糖凝胶电泳法测定了在好氧水溶液中经γ射线照射后的DNA单链断裂(SSB)的产率，照射后与碱基损伤修复内切酶甲酰胺嘧啶-DNA N-糖基酶(FPG)或核酸内切酶III(Endo III)孵育后，SSB的产量增加。在辐照过程中没有二甲基亚砜(DX；ISO)的情况下，这一增加与用气相色谱/质谱仪测定的已知的FPG和Endo III底物的产率一致。在1moldm(-3)DMSO存在下照射后，酶孵育后SSB产量的增加进一步增加了约5-7倍。这种影响的大小，丙烯酰胺或氧气不能抑制它，以及它被N，N，N‘，N’-四甲基苯二胺(TMPD)或甘油减弱，都表明甲基过氧基(来自DMSO)是参与其中的中间体，甲基过氧基(或由它衍生的其他物种)的反应不会导致链断裂损伤。但对FPG和Endo III承认的DNA碱基损伤负责。(C)1996年由辐射研究学会
Using agarose gel electrophoresis, we have measured the yields of DNA single-strand breaks (SSBs) for plasmid DNA gamma-irradiated in aerobic aqueous solution, Incubation after irradiation with the base damage repair endonucleases formamidopyrimidine-DNA N-glycosylase (FPG) or endonuclease III (endo III) results in an increase in the yield of SSBs. In the absence of dimethyl sulfoxide (DX;ISO) during irradiation, this increase is consistent with the yields of known substrates for FPG and endo III as determined by gas chromatography/mass spectrometry. After irradiation in the presence of 1 mol dm(-3) DMSO, the increase in the yield of SSBs after enzyme incubation was further enhanced by a factor of about 5 to 7. The magnitude of this effect, the inability of acrylamide or oxygen to suppress it, and its attenuation by N,N,N',N'-tetramethylphenylenediamine (TMPD) or glycerol all suggest that the methylperoxyl radical (derived from DMSO) is involved as an intermediate, Reactions of the methylperoxyl radical(or some other species derived from it) do not result in strand break damage, but are responsible for DNA base damages which are recognized by FPG and endo III. (C) 1996 by Radiation Research Society