Superoxide dismutase (SOD) catalyses the dismutation of superoxide radical. In humans, the cytosolic isoform of SOD contains which metal cofactors?

• A Iron and Molybdenum
• B Manganese alone
• C Selenium and Zinc
• D Copper and Zinc ✓

Explanation

Three SOD isoforms exist: SOD1 (cytosolic, Cu/Zn-SOD), SOD2 (mitochondrial matrix, Mn-SOD), and SOD3 (extracellular, Cu/Zn-SOD). SOD1 is the major cytosolic antioxidant dismutating O2•- to H2O2; gain-of-function SOD1 mutations cause familial ALS. Catalase and glutathione peroxidase (GPx, selenium-containing) then reduce H2O2 to water. Deficiency of Mn-SOD (SOD2) is lethal in mice due to mitochondrial ROS damage.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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