Toluene Diisocyanate Reactivity with Glutathione Across a Vapor/Liquid Interface and Subsequent Transcarbamoylation of Human Albumin

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• 作者：Adam V. Wisnewski ; Justin M. Hettick ; Paul D. Siegel
• 刊名：Chemical Research in Toxicology
• 出版年：2011
• 出版时间：October 17, 2011
• 年：2011
• 卷：24
• 期：10
• 页码：1686-1693
• 全文大小：879K
• 年卷期：v.24,no.10(October 17, 2011)
• ISSN：1520-5010

文摘

Glutathione has previously been identified as a reaction target for toluene diisocyanate (TDI) in vitro and in vivo, and has been suggested to contribute to toxic and allergic reactions to exposure. In this study, the reactivity of reduced glutathione (GSH) with TDI in vitro was further investigated using a mixed phase (vapor/liquid) exposure system to model the in vivo biophysics of exposure in the lower respiratory tract. HPLC/MS/MS was used to characterize the observed reaction products. Under the conditions tested, the major reaction products between TDI vapor and GSH were S-linked bis(GSH)-TDI and to a lesser extent mono(GSH)-TDI conjugates (with one N鈺怌鈺怬 hydrolyzed). The vapor-phase-generated GSH-TDI conjugates were capable of transcarbamoylating human albumin in a pH-dependent manner, resulting in changes in the self-protein鈥檚 conformation/charge, on the basis of electrophoretic mobility under native conditions. Specific sites of human albumin-TDI conjugation, mediated by GSH-TDI, were identified (Lys⁷³, Lys¹⁵⁹, Lys¹⁹⁰, Lys¹⁹⁹, Lys²¹², Lys³⁵¹, Lys^136/137, Lys^413/414, and Lys^524/525) along with overlap with those susceptible to direct conjugation by TDI. Together, the data extend the proof-of-principle for GSH to act as a 鈥渟huttle鈥?for a reactive form of TDI, which could contribute to clinical responses to exposure.