What Is A Free Radical - Ústav lékařské chemie a biochemie

Origin of superoxide from oxyhemoglobin
Štípek S et al.: Antioxidanty a volné radikály ve zdraví a nemoci. Grada
Publishing, Praha, 2000.
Superoxide
• Properties:
- Moderate reactivity, both oxidising and reducing
agent
- Limited ability to cross biological membranes (only
through anion channels or in its protonated form)
- Releases iron from Fe-S clusters
• Fate:
– Dismutation:
O 2·–
O 2·–
+ O 2·–
+ 2 H + → O 2 + H 2 O 2
– Reaction with nitric oxide:
NO· + O 2·–
→ OONO – (peroxynitrite)
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