This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins, Subject name: Biochemistry
All are antioxidant except - 
Select and explain. 
A. Vitamin A, B. Catalase, C. Cystein, D. Glutamine
D: Glutamine
Answer: D: Glutamine 
Explanation: Ans. is 'd' i.e., Glutamineo There are two types of antioxidant systems :-Enzymatic antioxidant systemThis includeCatalaseSuperoxide dismutase (SOD)Glutathione peroxidaseNon-enzymatic antioxidant systemThis is further subdivided intoVitamins : Vitamin E, Vitamin A & beta carotene. Vitamin C.Minerals : Selenium, Copper, Zinc, ManganeseTissue proteins : Transferrin, ferritin, lactoferrin, ceruloplasminAmino acids : Glutathione, Cysteine