Which trace element functions in glutathione peroxidase?

Which trace element functions in glutathione peroxidase?

• A. Selenium
• B. Zinc
• C. Copper
• D. Iron

Answer: (D)

Selenium is the trace element that functions in glutathione peroxidase because this enzyme is a selenoprotein with a selenocysteine residue at its active site, which is essential for catalyzing the reduction of hydrogen peroxide and lipid hydroperoxides using glutathione. The selenium-containing active site enables the enzyme to efficiently detoxify peroxides and protect cells from oxidative damage. Other common trace elements—zinc, copper, and iron—play roles in different enzymes and systems (zinc in many enzymes and transcription factors, copper in Cu/Zn superoxide dismutase, iron in various heme- or iron-dependent enzymes) but are not the required cofactor for glutathione peroxidase. Therefore, selenium is the correct choice.

Selenium is the trace element that functions in glutathione peroxidase because this enzyme is a selenoprotein with a selenocysteine residue at its active site, which is essential for catalyzing the reduction of hydrogen peroxide and lipid hydroperoxides using glutathione. The selenium-containing active site enables the enzyme to efficiently detoxify peroxides and protect cells from oxidative damage. Other common trace elements—zinc, copper, and iron—play roles in different enzymes and systems (zinc in many enzymes and transcription factors, copper in Cu/Zn superoxide dismutase, iron in various heme- or iron-dependent enzymes) but are not the required cofactor for glutathione peroxidase. Therefore, selenium is the correct choice.