This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Zinc is a cofactor of 
Select and explain. 
A. Alcohol dehydrogenase, B. Pyruvate Carboxylase, C. Pyruvate oxidase, D. None of the above
A: Alcohol dehydrogenase
Answer: A: Alcohol dehydrogenase 
Explanation: Metalloenzymes: These enzymes hold the metals rather tightly which are not readily exchanged. 
Alcohol dehydrogenase, carbonic anhydrase, alkaline phosphatase, carboxypeptidase and aldolase contain zinc.
Phenol oxidase (copper); Pyruvate oxidase (manganese); Xanthine oxidase (molybdenum); Cytochrome oxidase (iron and copper).
Satyanrayana, Ed 3, page no 91