This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: DNB 2018, Subject name: Biochemistry
Which of the following enzyme is free radical scavenger? 
Select and explain. 
A. Glutathione peroxidase, B. NADH oxidase, C. Hydrogen peroxidase, D. Hypochlorous
A: Glutathione peroxidase
Answer: A: Glutathione peroxidase 
Explanation: Antioxidant - that significantly delays or inhibits oxidation of a substrate. It may be considered as the scavengers of free radicals. ENZYMATIC oxidant - superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase Non enzymatic oxidant - vitamin E , VITAMIN C, VITAMIN A and selenium Glutathione peroxidase catalyzes the destruction of hydrogen peroxide. Fenton's reaction generates hydroxyl radical from H2O2 Superoxide dismutase generates H2O2from superoxide NADPH oxidase reaction generates superoxide from oxygen