Zinc is an essential component of the following enzymes except: (A) Carbonic anhydrase, (B) Alkaline phosphate, (C) Xanthine oxidase, (D) Ethanol dehydrogenase
Answer is C. Xanthine oxidase and aldehyde oxidase contain molybdoprotein, a substituted pterin to which molybdenum is bound by two sulfur atoms. Mo deficiency causes depression of xanthine oxidase activity, increased excretion of xanthine and decreased uric acid excretion.Ref: DM Vasudevan, page no: 430