Peroxidase catalysed oxygen activation by arylamine carcinogens and phenol

Peroxidase catalysed the formation of active oxygen in the presence of NADH or GSH and traces of H2O2 and arylamine or phenolic substrates. Some oxygen activation occurred with some arylamines even in the absence of NADH or GSH. Oxygen consumption was proportional to the NADH oxidized or GSSG formed. Approximately 0.80 and 0.40 mol of oxygen were consumed per mole of NADH or GSH oxidized respectively. The requirement for trace amounts of hydrogen peroxide and arylamine or phenolic substrates suggest that redox cycling resulted in H2O2 formation. It is proposed that initially formed phenoxy radicals or arylamine cation radicals oxidize NADH or GSH to radicals which react with oxygen to form superoxide radicals and H2O2.