This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins and Minerals, Subject name: Biochemistry
Selenium is essential for the: 
Select and explain. 
A. Glutathione peroxidase, B. Glutathione reductase, C. Glutathione synthetase, D. Glutathione hydroxylase
A: Glutathione peroxidase
Answer: A: Glutathione peroxidase 
Explanation: Ans. A. Glutathione peroxidasea. Glutathione peroxidase is a selenium containing enzyme which acts in synergism with vitamin E to protect against hydroperoxide free radical damage.b. First line of defense against hydroperoxide free radical damage is vitamin E (tocopherol) while the second line of defense is a selenium containing enzyme glutathione peroxidase.