The role of superoxide radical in chromium(VI)-generated hydroxyl radical: the Cr(VI) Haber-Weiss cycle.
Arch Biochem Biophys 1992 Jan; 292(1):323-327
The role of the superoxide radical (O2) in the cellular injury caused by exposure to chromium (7440473) (Cr) was investigated. Cr(VI) catalyzed the formation of the hydroxyl radical from superoxide by a Haber-Weiss type of cycle. Electron spin resonance and spin trapping techniques were used to monitor the formation of Cr(V) from the reduction of Cr(VI) by the superoxide radical and the subsequent generation of the hydroxyl radical by reaction of the Cr(V) species with hydrogen-peroxide. This work provided the first experimental evidence that Cr(VI) is capable of catalyzing a Haber- Weiss cycle to generate hydroxyl radicals; further, it offered a clue as to why molecular oxygen plays a fundamental role in the genotoxic reactions associated with exposure to Cr(VI) containing compounds. The usefulness of antioxidants as antagonists toward Cr(VI) related genotoxicity was implied.
NIOSH-Publication; NIOSH-Cooperative-Agreement; Genotoxic-effects; Cell-damage; Cytotoxic-effects; Hexavalent-chromium-compounds; Biotransformation; Free-radicals; Carcinogens
Archives of Biochemistry and Biophysics
Center to Protect Workers' Rights