title: Chemical structure of the adducts formed by the oxidation of benzidine in the presence of phenols.
abstract: Bioactivation of carcinogens by peroxidases has received increasing attention since the discovery of the oxidation of carcinogens by prostaglandin hydroperoxidase. Benzidine and 3,5,3',5'-tetramethylbenzidine are oxidized by horseradish peroxidase and prostaglandin synthase to two-electron oxidation products (di-imines). Di-imines readily react with the phenolic anti-oxidant butylated hydroxyanisole to form adducts. In this paper, we have studied the oxidation of benzidine by horseradish peroxidase in the presence of phenolic compounds and characterized the resultant benzidine/phenol adducts. A benzidine/2,6-dimethylphenol adduct was isolated and characterized by mass spectrometry and high field n.m.r. The reaction of [14C]benzidine in the presence of horseradish peroxidase and phenol yielded only the benzidine/phenol adduct. Our results indicate that the benzidine/phenol adducts are analogous to the indoaniline dyes, differing only in substitution of a biphenyl group for a benzene ring. The reaction of benzidine di-imine with endogenous phenols may represent a new pathway for detoxication, removing potentially harmful metabolites of benzidine.
mesh_terms: D001560:Benzidines; D002250:Carbon Radioisotopes; D055598:Chemical Phenomena; D002621:Chemistry; D002855:Chromatography, Thin Layer; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010636:Phenols; D013329:Structure-Activity Relationship
chemical_list: D001560:Benzidines; D002250:Carbon Radioisotopes; D010636:Phenols