Agarwal S, Draper H H
Department of Nutritional Sciences, College of Biological Science, University of Guelph, Ontario, Canada.
Free Radic Biol Med. 1992 Dec;13(6):695-9. doi: 10.1016/0891-5849(92)90043-g.
In previous studies, an adduct of malondialdehyde (MDA) with guanine was identified in rat and human urine. Subsequent detection of an adduct with deoxyguanosine (dG) in urine prompted an investigation of its possible occurrence in DNA. Rat liver DNA was hydrolyzed using nuclease P1 and alkaline P-ase and subjected to deoxyribonucleoside analysis using reverse phase high-pressure liquid chromatography (HPLC) with fluorescence detection. A compound was isolated that could not be separated from a synthetic pyrimidinopurine adduct of MDA and dG (dG-MDA). Partial hydrolysis released guanine (Gua), Gua-MDA, and dG in amounts that, in aggregate, were the molar equivalent of the starting material calculated by fluorescence analysis as dG-MDA. Complete acid hydrolysis of the isolate yielded an equimolar amount of MDA. Analysis of liver DNA isolated from growing rats yielded a value for dG-MDA content of 9.0 +/- 1.6 pmol/100 micrograms DNA (mean +/- SEM, N = 5). This value is approximately 7 times those reported for the 8-hydroxy deoxyguanosine content of rat liver nuclear DNA. This study demonstrates that DNA is modified in vivo by reactions of its guanylate moiety with MDA, and indicates that, at least in the case of rat liver DNA, the prevalence of such modifications is greater than those caused by reactions with hydroxyl radicals.
在先前的研究中，在大鼠和人类尿液中鉴定出丙二醛（MDA）与鸟嘌呤的加合物。随后在尿液中检测到与脱氧鸟苷（dG）的加合物，促使人们对其在DNA中可能的存在情况进行研究。使用核酸酶P1和碱性磷酸酶水解大鼠肝脏DNA，并通过带有荧光检测的反相高压液相色谱（HPLC）进行脱氧核糖核苷分析。分离出一种化合物，它无法与MDA和dG的合成嘧啶嘌呤加合物（dG-MDA）分离。部分水解释放出鸟嘌呤（Gua）、Gua-MDA和dG，其总量通过荧光分析计算为dG-MDA，与起始物质的摩尔当量相当。分离物的完全酸水解产生等摩尔量的MDA。对从生长大鼠分离的肝脏DNA进行分析，得出dG-MDA含量为9.0 +/- 1.6 pmol/100微克DNA（平均值 +/- 标准误，N = 5）。该值约为大鼠肝脏核DNA中8-羟基脱氧鸟苷含量报告值的7倍。这项研究表明，DNA在体内会因其鸟苷酸部分与MDA的反应而发生修饰，并表明，至少在大鼠肝脏DNA的情况下，这种修饰的发生率高于与羟基自由基反应所导致的修饰。
