马兜铃酸-脱氧核糖核酸加合物的质谱分析

马兜铃酸(aristolochic acid,AA)经酶活化法(黄嘌呤氧化酶法)和化学活化法(锌法)活化后与脱氧腺苷酸在弱酸环境下反应合成了AA-DNA加合物。采用多种质谱技术对加合物进行了鉴定。电喷雾-质谱法(ESI-MS)负离子采集模式下测得其准分子离子峰分别为m/z621和591;利用多级串联质谱(MSn)等方法,得到了加合物的结构信息;应用傅里叶变换离子回旋共振质谱(FT-ICRMS)精确质量数测定和同位素模式检测进一步确认了目标化合物。结果表明,质谱法分析AA-DNA加合物方便、准确、可靠,优于国外文献报道的32P-后标记法。

Mass Spectrometric Analysis for Aristolochic Acid-Deoxyribonucleic Acid Adducts

Aristolochic acid(AA) was incubated with 2'-deoxyadenosine 5'-monophosphate(dAp) in mild acid phosphate buffer in vitro for 12 hours,using either enzymatic activation(by xanthine oxidase) or chemical activation(by zinc) to synthesize AA-DNA adducts,and the solvents were evaporated under vacuum.The AA-DNA adducts were characterized by multiple mass spectrometric techniques.Electrospray ionization/tandem mass spectrometry(ESI-MS/MS) was used for the characterization of the AA-DNA adducts.Full scan spectra were obtained in the negative ion mode and the quasi-molecular ion peaks of the AA-DNA adducts were m/z 621 and m/z 591 respectively.Crude extracts were analyzed by ESI-MSn technique to investigate structural information about the fragmentation rules of AA-DNA adducts in negative mode.Using the high accuracy mass data and isotope pattern of super high resolution Fourier transform-ion cyclotron resonance mass spectrometry(FT-ICRMS),the AA-DNA adducts were identified further.The results indicated that AA-DNA adducts were synthesized in vitro successfully.This method is a powerful tool for detection and identification of AA-DNA adducts.Compared with 32P-postlabelling analysis this method has the advantages of simple operation,rapid measurement and accurate determination.