Within injured tissue, superoxide generated by NADPH oxidase can be converted into the most reactive oxygen species capable of attacking DNA bases and lipid membranes. The reaction responsible, requiring ferrous iron, is known as:
- A Haber-Weiss reaction catalysed by superoxide dismutase
- B Glutathione redox cycle reducing lipid hydroperoxides
- C Fenton reaction converting hydrogen peroxide to hydroxyl radical ✓
- D Myeloperoxidase-halide system generating hypochlorous acid
Correct answer: C. Fenton reaction converting hydrogen peroxide to hydroxyl radical
Explanation
The Fenton reaction uses ferrous iron to split hydrogen peroxide into hydroxyl ion and hydroxyl radical, the most reactive oxygen species produced biologically. Superoxide dismutase first converts superoxide to hydrogen peroxide, which then becomes Fenton substrate, while the uncatalysed Haber-Weiss reaction is too slow to matter physiologically. Myeloperoxidase generates HOCl, a potent antimicrobial agent but less reactive toward DNA than hydroxyl radical.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.