Redox Homeostasis is Disturbed by Redox Cycling between Reactive Cysteines of Thioredoxin 1 and 9,10-Phenanthrenequinone, an Atmospheric Electron Acceptor.

9,10-Phenanthrenequinone (9,10-PQ) is a toxicant in diesel exhaust particles and airborne particulate matter ≤2.5 μm in diameter. It is an efficient electron acceptor that readily reacts with dithiol compounds , resulting in the oxidation of thiol groups and concomitant generation of reactive oxygen species (ROS).

Interaction of 9,10-phenanthraquinone with dithiol causes oxidative modification of Cu,Zn-superoxide dismutase (SOD) through redox cycling.

9,10-Phenanthraquinone (9,10-PQ) is abundant in diesel exhaust particles (DEP) and causes oxidative protein modification in cells. We previously reported that redox cycling of 9,10-PQ with dithiols leads to the generation of an excess of superoxide (O₂•⁻). Cu,Zn-superoxide dismutase (Cu,Zn-SOD), which dismutates O₂•⁻ to hydrogen peroxide (H₂O₂), is sensitive to its own product, H₂O₂.