Breaking the dogma: PCB-derived semiquinone free radicals do not form covalent adducts with DNA, GSH, and amino acids.

ABSTRACT: Covalent bond formations of free radical metabolites with biomolecules like DNA and proteins are thought to constitute a major mechanism of toxicity and carcinogenesis. Glutathione (GSH) is generally accepted as a radical scavenger protecting the cell. In the present study, we investigated a semiquinone radical (SQ(●-)) metabolite of the semivolatile 4-chlorobiphenyl, using electron paramagnetic resonance spectroscopy, and oxygen consumption. Proton nuclear magnetic resonance ((1)H NMR) and liquid chromatography-mass spectrometry (LC-MS) were also employed to elucidate the radical interaction with DNA, amino acids, and GSH. We found that DNA and oligonucleotides stabilized SQ(●-) by electron delocalization in the π-stacking system, resulting in persistent radical intercalated, rather than

SUBMITTER: Wangpradit O 

PROVIDER: S-EPMC4767158 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature