Iron-ethylenediaminetetraacetic acid (EDTA)-catalyzed superoxide dismutation revisited: An explanation of why the dismutase activity of Fe-EDTA cannot be detected in the cytochrome c/xanthine oxidase assay system

Abstract

The recent assertion of [1.] that Fe-EDTA does not catalyze superoxide dismutation is disputed. By directly observing superoxide generated during pulse radiolysis, we have confirmed the results of a previous study ( [2.]) which concluded that Fe-EDTA catalyzed superoxide dismutation. We also demonstrate that the reaction of Fe(II)-EDTA, formed during catalyzed superoxide dismutation, with cytochrome c, the probe molecule in the cytochrome c/xanthine oxidase/xanthine assay system for superoxide dismutase activity, is sufficiently rapid ([12.]) to obscure the weak catalysis of superoxide dismutation by Fe-EDTA.