Identification of DNA adducts of methylglyoxal
Identification of DNA adducts of methylglyoxal
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DOI：
10.1021/tx0501278
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发表时间：
2005-10-01
影响因子：
4.1
通讯作者：
Pischetsrieder, M
中科院分区：
文献类型：
--
作者：
Frischmann, M;Bidmon, C;Pischetsrieder, M
甲基乙二醛（MG）是一种糖降解产物，是在糖酵解、丙酮的酮体代谢和苏氨酸分解代谢过程中磷酸丙糖裂解而内源形成的。食品、饮料和医疗产品是重要的外源来源，其浓度高达 100 μM MG。 MG 是一种反应性二羰基化合物，很容易修饰蛋白质的氨基（糖化反应），从而诱导促炎反应。此外，据报道，用 MG 治疗后哺乳动物细胞的突变频率增加，这是由 DNA 碱基的稳定修饰引起的。迄今为止，已鉴定出两种类型的加合物，它们是在游离鸟嘌呤或2'-脱氧鸟苷与高MG浓度反应期间形成的。在这项研究中，我们研究了 DNA 长时间暴露于生理 MG 浓度的情况。 DNA 与 MG 一起孵育，酶促水解以释放游离核苷，然后通过 LC-MS/MS 进行分析。我们检测到四种产物，它们是由 2'-脱氧鸟苷和 2'-脱氧腺苷分别与 1 和 2 当量 MG 反应得到的。与 1 当量 MG 的加合物被鉴定为 N-2-(1-羧乙基)-2'-脱氧鸟苷 (CEdG) 和 N-6-(1-羧乙基)-2'-脱氧腺苷。针对这些化合物优化了 LC-MS/MS，并使用生理浓度 10,μM MG 重复孵育 DNA。因此，CEdG 被证明是 DNA 与 MG 反应最敏感、最合适的标记物（阴性 MRM 模式，三个质量转变 [M - 1](-) 338 -> 178、338 -> 106 和 338 -> 149）。
Methylglyoxal (MG) is a sugar degradation product, which is endogenously formed by fragmentation of triose phosphates during glycolysis, ketone body metabolism of acetone, and catabolism of threonine. Food, beverages, and medical products are important exogenous sources with concentrations of up to 100 mu M MG. MG is a reactive dicarbonyl compound, which easily modifies amino groups of proteins (glycation reaction) and thereby induces proinflammatory responses. Moreover, increased mutation frequencies in mammalian cells after treatment with MG have been reported, which are caused by stable modifications of DNA bases. Thus far, two types of adducts have been identified, which are formed during the reaction of free guanine or 2'-deoxyguanosine with high MG concentrations. In this study, we investigated the prolonged exposure of DNA to physiological MG concentrations. DNA was incubated with MG, enzymatically hydrolyzed to release the free nucleosides, and then analyzed by LC-MS/MS. We detected four products, which were derived from the reaction of 2'-deoxyguanosine and 2'-deoxyadenosine with 1 and 2 equiv of MG each. The adducts with 1 equiv of MG were identified as N-2-(1-carboxyethyl)-2'-deoxyguanosine (CEdG) and N-6-(1-carboxyethyl)-2'-deoxyadenosine. LC-MS/MS was optimized for these compounds, and incubation of DNA was repeated using physiological concentrations of 10,mu M MG. Thereby, CEdG proved to be the most sensitive and suitable marker for the reaction of DNA with MG (negative MRM mode, three mass transitions [M - 1](-) 338 -> 178, 338 -> 106, and 338 -> 149).