This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cofactor and prosthetic groups, Subject name: Biochemistry
All of the following are true about Xanthine oxidase, EXCEPT: 
Select and explain. 
A. Contains iron, B. Contains molybdenum, C. Flavoprotein, D. Produces H2O
D: Produces H2O
Answer: D: Produces H2O 
Explanation: Xanthine oxidase is a flavoprotein containing both molybdenum and iron-sulphur clusters. Deficiency of xanthine oxidase leads to hyperuricemia. Look at the reaction. Xanthine oxidase produces H2O2(Hydrogen peroxide), not H2O.