This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Enzymes, Subject name: Biochemistry
Carboxypeptidase contains which mineral? 
Select and explain. 
A. Copper, B. Zinc, C. Iron, D. None
B: Zinc
Answer: B: Zinc 
Explanation: More than 300 enzymes are zinc-dependent. Some impoant ones are carboxypeptidase, carbonic anhydrase, alkaline phosphatase, lactate dehydrogenase, alcohol dehydrogenase and glutamate dehydrogenase. RNA polymerase contains zinc and so it is required for protein biosynthesis. Extracellular superoxide dismutase is zinc-dependent and so, zinc has antioxidant activity.Ref: DM Vasudevan, page no: 429