Chromatographic and spectrophotometric characterization of adducts formed during the reaction of trans,trans-muconaldehyde with 14C-deoxyguanosine 5'-phosphate.

Abstract

Mice liver microsomes oxidatively open the benzene ring to form trans,trans-muconaldehyde, a hematotoxic unsaturated aldehyde. In the present studies, 4.5 mumole trans,trans-muconaldehyde was reacted with 14C-2'deoxyguanosine 5'-phosphate in phosphate buffer. Products were separated by high performance liquid chromatography (HPLC). Absorbance was monitored using a diode array detector, and aliquots of the HPLC eluant were collected for UV spectrophotometric analysis and scintillation counting. Under these conditions, deoxyguanosine 5'-phosphate eluted at 12.5 min and muconaldehyde at 22.0 min. The HPLC and radioactivity profiles of the muconaldehyde/deoxyguanosine reaction mixture indicated the presence of multiple adducts. Three adducts were detected eluting at 36, 39, and 42 min, which represented approximately 2.5, 2.5, and 1% of the radioactivity, respectively. These adducts had similar UV spectra with absorption maxima between 334 and 347 nm. Another product of the reaction mixture, eluting at 19.0 min and accounting for 10% of the radioactivity, was also observed. This compound had absorption maxima at 348 and 372 nm. These results suggest that trans,trans-muconaldehyde can react with deoxyguanosine monophosphate in vitro under physiological conditions to form stable adducts. Studies are being conducted to determine the structure of these adducts and whether these adducts are formed by the reaction of DNA with muconaldehyde or metabolically activated benzene.