fig1

Figure 1. Principle of the Perotox assay. The Perotox enzyme assay is based on the production of oxygen radicals during the PER reaction of H₂O₂ and a reducing substrate. Both H₂O₂ and the oxidized products could, in turn, oxidize various proxy substrates in addition to luminol, such as an unsaturated lipid (Tween-80), protein (albumin), and DNA. The oxidation of unsaturated carbons of Tween-80 detergent leads to peroxidation (aldehyde formation), while interaction with DNA leads to DNA strand breaks. The addition of DNA during the PER reaction with H₂O₂ and lumino/fluorogenic substrate (luminol or dihydrofluorescein) could also protect PER against inhibition by the xenobiotics, the so-called DNA protection assay. Perotox: Peroxidase-toxicity; PER: peroxidase.