Biological Effects of and Responses to Exposure to Electrophilic Environmental Chemicals

Abstract

Electrophiles readily bind to nucleophilic centers on intracellular macromolecules such as DNA and proteins. Electrophilic attack on DNA results in the formation of an adduct, leading to depurination due to hydrolysis of a purine base such as adenine or guanine. On the other hand, electrophiles also attack proteins, with the thiolate function as the most attractive site. Many protein cysteine (Cys) thiols are affected by their proximity to basic amino acids, which results a decrease in the thiol pKa value. This paper discusses the role of electrophile-nucleophile interactions in the adverse health effects of electrophilic environmental chemicals such as arsenic compounds (groundwater contaminant), methylmercury (MeHg; a fish contaminant), and 1,2-naphthoquinone (1,2-NQ; an atmospheric contaminant).