γ射线辐照的DNA、脱氧核苷酸和脱氧核苷中的丙二醛前体。
Malondialdehyde precursors in gamma-irradiated DNA, deoxynucleotides and deoxynucleosides.
作者信息
Janicek M F, Haseltine W A, Henner W D
出版信息
Nucleic Acids Res. 1985 Dec 20;13(24):9011-29. doi: 10.1093/nar/13.24.9011.
Gamma-irradiation of DNA, deoxynucleosides, or deoxynucleotides produces material that reacts with thiobarbituric acid to form a chromophore with maximum absorbance at 532 nm. This material is not malondialdehyde. We have identified a new radiation product (thymin-1'-yl)-propenal as the TBA-reactive product of gamma-irradiation of thymidine. Thymine-propenal has been described by other investigators as a product of bleomycin-treatment of DNA. Irradiation of thymidine nucleotides produces phosphorylated precursors to thymine-propenal. Studies of the requirements for formation of TBA-reactivity indicate a mechanism involving reaction of a free radical with the deoxyribose moiety and molecular oxygen. On the basis of these results it is proposed that gamma-irradiation produces TBA-reactive material in DNA by the same reaction sequence in which bleomycin catalyzes the formation of base-propenals in DNA. Bleomycin and gamma-irradiation differ in the extent to which the sequence proceeds to completion with release of free base-propenals.
对DNA、脱氧核苷或脱氧核苷酸进行γ射线照射会产生一种能与硫代巴比妥酸反应的物质，该物质会形成一种在532nm处有最大吸光度的发色团。这种物质不是丙二醛。我们已鉴定出一种新的辐射产物（胸腺嘧啶-1'-基）-丙烯醛，它是γ射线照射胸腺嘧啶核苷产生的与硫代巴比妥酸反应的产物。胸腺嘧啶-丙烯醛已被其他研究人员描述为博来霉素处理DNA的产物。照射胸腺嘧啶核苷酸会产生胸腺嘧啶-丙烯醛的磷酸化前体。对形成硫代巴比妥酸反应活性的条件的研究表明，其机制涉及自由基与脱氧核糖部分和分子氧的反应。基于这些结果，有人提出γ射线照射通过与博来霉素催化DNA中碱基-丙烯醛形成相同的反应序列，在DNA中产生与硫代巴比妥酸反应的物质。博来霉素和γ射线照射在该序列进行到何种程度会释放游离碱基-丙烯醛方面存在差异。
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