Selenium is an essential trace element required as selenocysteine in which important antioxidant enzyme?

• A Superoxide dismutase (Cu-Zn SOD)
• B Catalase
• C Glutathione reductase
• D Glutathione peroxidase (GPx) ✓

Explanation

Selenium is incorporated as selenocysteine (the 21st amino acid) at the active site of glutathione peroxidases (GPx1–4); GPx uses GSH to reduce H2O2 and phospholipid hydroperoxides. Selenium deficiency causes Keshan disease (cardiomyopathy). SOD requires copper and zinc (Cu-Zn SOD) or manganese (Mn-SOD). Catalase uses iron. Glutathione reductase requires FAD and NADPH but no selenium.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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