The Fenton reaction is a key source of highly reactive hydroxyl radicals in biological systems. Which ion is the MOST important catalyst in the Fenton reaction in vivo?
- A Copper (Cu+) and Iron (Fe2+) ✓
- B Zinc (Zn2+)
- C Selenium (Se2-)
- D Manganese (Mn2+)
Correct answer: A. Copper (Cu+) and Iron (Fe2+)
Explanation
In the Fenton reaction, Fe2+ (and Cu+) reacts with H2O2 to produce the highly reactive hydroxyl radical (•OH): Fe2+ + H2O2 → Fe3+ + •OH + OH-. Fe3+ is then reduced back to Fe2+ by superoxide (Haber-Weiss reaction), completing the cycle. This is why free iron and copper are extremely pro-oxidant — they catalyse •OH generation from the relatively stable H2O2. Iron chelation (deferoxamine) and transferrin/lactoferrin binding limit this Fenton chemistry in vivo.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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