Adduction of DNA with MTBE and TBA in mice studied by accelerator mass spectrometry

Methyl tert-butyl ether (MTBE) is a currently worldwide used octane enhancer substituting for lead alkyls and gasoline oxygenate. Our previous study using doubly ¹⁴C-labeled MTBE [(CH₃)₃¹⁴CO¹⁴CH₃] has shown that MTBE binds DNA to form DNA adducts at low dose levels in mice. To elucidate the mechanism of the binding reaction, in this study, the DNA adducts with singly ¹⁴C-labeled MTBE, which was synthesized from ¹⁴C-methanol and tert-butyl alcohol (TBA), or ¹⁴C-labeled TBA in mice have been measured by ultra sensitive accelerator mass spectrometry. The results show that the methyl group of MTBE and tert-butyl alcohol definitely form adducts with DNA in mouse liver, lung, and kidney. The methyl group of MTBE is the predominant binding part in liver, while the methyl group and the tert-butyl group give comparable contributions to the adduct formation in lung and kidney. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 630-635, 2007.