Table 2.
| Antioxidant enzyme | Function | Chemical reaction |
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| Superoxide dismutase | Catalysing superoxide anion to oxygen and hydrogen peroxide | 2O2 • + 2H+ → H2O2 + O2 |
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| Catalase | Detoxifying hydrogen peroxide to water and oxygen molecule | 2H2O2 → O2 + 2H2O |
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| Glutathione (GSH) | Electron donor to GPx in reducing hydroperoxides to water molecules | 2GSH + H2O2 → GS–SG + 2H2O |
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| Glutathione peroxidase | Reducing hydroperoxides to water molecules | 2GSH + H2O2→ GS–SG + 2H2O |
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| Glutathione reductase | Catalyzing the reduction of glutathione disulfide (GSSG) to the sulfhydryl form glutathione (GSH) | GSSG + NADPH + H+ → 2GSH + NADP+ |
O 2 • (superoxide anion); H 2 O 2 (hydrogen peroxide); O 2 (oxygen); H 2 O (water molecule); GSSG (reduced glutathione); NADPH (nicotinamide adenine dinucleotide phosphate).