Lipid hydroperoxide activation of N-hydroxy-N-acetylaminofluorene via a free radical route.

The data presented here demonstrate that linoleic acid hydroperoxide in the presence of methemoglobin or hematin activated the carcinogen N-hydroxy-N-acetyl-2-amino-fluorene via the nitroxyl free radical intermediate into 2-nitrosofluorene and N-acetoxy-N-acetyl-2-aminofluorene. Ascorbate inhibited the activation, in which case the free radical intermediate was replaced by the ascorbate free radical. On the basis of optical kinetics, we have established that the rate of linoleic acid hydroperoxide decrease paraleled the rate of N-hydroxy-N-acetyl-2-aminofluorene decrease and also the rate of 2-nitrosofluorene increase. The stoichiometry of the reaction was such that, for every 2 linoleic acid hydroperoxide molecules consumed, 2 N-hydroxy-N-acetyl-2-aminofluorene molecules were oxidized and 1 2-nitrosofluorene and 1 N-acetoxy-N-acetyl-2 aminofluorene molecule was formed.