Trace element present in carbonic anhydrase is?

Zn is an essential component of several enzymes like carbonic anhydrase, alcohol dehydrogenase, alkaline phosphatase, carboxypeptidase and superoxaide dismutase. The carbonic anhydrases (or carbonate dehydratases) form a family of enzymes that catalyze the rapid interconversion of carbon dioxide and water to bicarbonate and protons (or vice versa), a reversible reaction that occurs rather slowly in the absence of a catalyst. The active site of most carbonic anhydrases contains a zinc ion; they are therefore classified as metalloenzymes. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 39. Acidification of the Urine & Bicarbonate Excretion. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.