title: Free radical activation of N-hydroxy-2-acetylaminofluorene by methemoglobin and hydrogen peroxide.
abstract: We have shown that N-hydroxy-2-acetylaminofluorene, a metabolite of 2-acetylaminofluorene, is converted via a nitroxide free radical into N-acetylaminofluorene and 2-nitrosofluorene by H2O2 in the presence of methemoglobin. Utilizing optical methods, we have demonstrated that the rate of 2-nitrosofluorene production parallels that of N-hydroxy-2-acetylaminofluorene oxidation. This evidence is consistent with a model whereby two molecules of N-hydroxy-2-acetylaminofluorene yield two nitroxide free radicals which then dismutate to form one molecule of N-acetoxy-2-acetylaminofluorene and one molecule of 2-nitrosofluorene. The Km of N-hydroxy-2-acetylaminofluorene for this reaction is 114 microM with a Vmax of 50 microM/min.
mesh_terms: D015073:2-Acetylaminofluorene / Q000031:analogs & derivatives; D000818:Animals; D002417:Cattle; D005609:Free Radicals; D006861:Hydrogen Peroxide; D006881:Hydroxyacetylaminofluorene; D007700:Kinetics; D008706:Methemoglobin; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005609:Free Radicals; D006881:Hydroxyacetylaminofluorene; D008706:Methemoglobin; D015073:2-Acetylaminofluorene; D006861:Hydrogen Peroxide