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 imole trans,trans-muconaldehyde was reacted with "4C-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.

Deoxyguanosine Forms a Bis-Adduct with E,E-Muconaldehyde, an Oxidative Metabolite of Benzene: Implications for the Carcinogenicity of Benzene

“…The reactions were monitored by HPLC. Within a few hours several small peaks appeared and additional peaks appeared over the course of several days, several of which had UV spectra similar to those reported by Latriano et al 17 ESI-MS of the early mixtures showed the presence of species containing dGuo and muconaldehyde in a 1:1 ratio with and without loss of water; 2:1 species from which 0, 1 and 2 water molecules had been lost were also observed. An interpretation of these results is presented in the Discussion section.…”

“…Latriano et al demonstrated that the reaction of E,E -muconaldehyde with 14 C-labeled dGuo-5´-phosphate in phosphate buffer, pH 7.4 yielded several radioactive products of unknown structure. 17 …”

Metabolism and Toxicity of trans,trans-Muconaldehyde, an Open-Ring Microsomal Metabolite of Benzene

“…Well-resolved minor peaks were detected at retention times of 2.8, 9.9, and 20.2 min, and a group of six peaks eluted between 5.6 and 8.7 min. These results are similar to those obtained in collaborative work with Latriano et al (26) who used radiolabeled deoxyguanosine 5'-phosphate in the reaction with TTM. Alpha,betaunsaturated aldehydes have been reported to react with deoxyguanosine, forming products with one additional ring involving the N-1 position and the amino group on C-2 (27,28).…”

Reactions of muconaldehyde isomers with nucleophiles including tri-O-acetylguanosine: Formation of 1,2-disubstituted pyrroles from reactions of the (Z,Z)-isomer with primary amines

“…9 Reactions of (2,Z)-muconaldehyde with nucleosides provides a basis for understanding the molecular mechanism of mutagenesis by this aldehyde. In a previous study (27) @,E)-muconaldehyde was reacted with [Wdeoxyguanosine 5'-phosphate, but the structures of products observed chromatographically were not determined. We have found that reaction of (2,Z)-muconaldehyde with 2,3,5-tri-O-acetylguanosine gives adduct Sa, the structure of which was assigned by analogy to 7.…”