Glutathione Peroxidase

Definition

A selenoprotein enzyme that reduces harmful hydroperoxides to water and alcohol. Essential for protecting cells from lipid peroxidation and hydrogen peroxide damage.

How it works

Glutathione peroxidase (GPx) is a family of selenoproteins that catalyze the reduction of organic hydroperoxides and hydrogen peroxide to their corresponding alcohols and water, protecting cells from peroxide-induced damage. This enzyme requires selenium as a structural component of its catalytic site and glutathione as a reducing substrate. GPx works synergistically with catalase and superoxide dismutase as part of the cell's antioxidant defense system. Selenium intake directly influences GPx synthesis, making adequate selenium consumption critical for antioxidant capacity.

Role

Catalytically converts hydroperoxides into harmless products, preventing lipid peroxidation.

Examples

• Reducing lipid hydroperoxides
• Converting hydrogen peroxide
• Protecting red blood cells
• Supporting thyroid hormone synthesis
• Defending against xenobiotic stress

Recommendations

Ensure adequate selenium intake (55 mcg daily) from Brazil nuts, fish, poultry, and whole grains. Combine with adequate protein intake to support GPx synthesis. Avoid excessive selenium supplementation which impairs GPx function.

Key takeaway

Selenium-dependent glutathione peroxidase is essential for complete antioxidant defense.

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