Characterization and Quantification of Cysteinyl Adducts of Benzene Diol Epoxide

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• 作者：Suramya Waidyanatha ; Ramiah Sangaiah ; and Stephen M. Rappaport
• 刊名：Chemical Research in Toxicology
• 出版年：2005
• 出版时间：July 2005
• 年：2005
• 卷：18
• 期：7
• 页码：1178 - 1185
• 全文大小：186K
• 年卷期：v.18,no.7(July 2005)
• ISSN：1520-5010

文摘

The production of macromolecular adducts of benzene diol epoxide (BDE), a toxic metaboliteof benzene, has received little attention despite the demonstrated mutagenicity and carcinogenicity of BDE in rodents. Syn and anti enantiomers of BDE were relatively stable in 0.1 Mammonium acetate buffer, pH 7.6 (half times were greater than 5 h), and showed evidence ofpseudo-first-order reactions with albumin (half times were about 4 h) and glutathione (GSH)(half times were about 0.3-0.4 h). Reaction products of BDE isomers with L-cysteine, N-acetyl-L-cysteine, N-acetyl-L-cysteine methyl ester, and GSH were characterized by a combination ofelectrospray ionization mass spectrometry and/or gas chromatography-mass spectrometry withelectron impact ionization of trimethylsilyl derivatives of the adducts. Products correspondedto 1:1 addition of BDE isomers with each nucleophilic species, suggesting that adductionoccurred primarily at the free sulfhydryl group. To investigate the disposition of the BDEs invivo, we developed an assay for cysteinyl BDE-protein adducts. The assay involves enzymatichydrolysis of the protein followed by derivatization of the released adducts and gas chromatography-negative ion chemical ionization-mass spectrometry. Preliminary applications of theassay showed linear increases in the formation of BDE-GSH adducts in samples of GSHincubated with increasing concentrations of BDE (10-300 mages/entities/mgr.gif">M) and showed the presence ofBDE-albumin following incubation of albumin with 10 mages/entities/mgr.gif">M BDE.