title: Obligatory free radical intermediate in the oxidative activation of the carcinogen N-hydroxy-2-acetylaminofluorene.
abstract: We have demonstrated that the nitroxyl free radical form of the carcinogen N-hydroxy-2-acetylaminofluorene (OH-AAF) is an obligatory intermediate in the cumene hydroperoxide-hematin-induced oxidative activation of this carcinogen into 2-nitrosofluorene and N-acetoxy-2-acetylaminofluorene. Both the rate of N-OH-acetylaminofluorene oxidation and the amount of its nitroxyl free radical were experimentally observed as a function of reaction time. Rate equations were derived for a model in which the nitroxyl free radical form of OH-AAF was an obligatory intermediate in the reaction. Using this theory it was possible to compute one experimental variable, the rate of OH-AAF oxidation, utilizing the other experimental variable, the amount of nitroxyl free radical present at any time during the reaction. The theory also predicts a linear relationship between the rate of OH-AAF oxidation and the square of the free radical content; and this was found to be true experimentally. The dismutation rate constant of the nitroxyl free radical of OH-AAF was found to be 2.7-10(5) M-1-s-1.
mesh_terms: D005449:Fluorenes / Q000378:metabolism; D005609:Free Radicals; D006881:Hydroxyacetylaminofluorene / Q000378:metabolism; D007700:Kinetics; D008433:Mathematics; D010084:Oxidation-Reduction
chemical_list: D005449:Fluorenes; D005609:Free Radicals; D006881:Hydroxyacetylaminofluorene