Step 1: Understanding the Concept:
Xanthine oxidoreductase is a complex metalloflavoenzyme containing molybdopterin (Mo-pterin), iron-sulfur centers, and FAD cofactors. Key Formula or Approach:
\[ \text{Hypoxanthine} \xrightarrow{\text{Xanthine Oxidase [Mo]}} \text{Xanthine} \xrightarrow{\text{Xanthine Oxidase [Mo]}} \text{Uric Acid} \] Step 2: Detailed Explanation: Xanthine Oxidase (XO): - A homodimeric metalloenzyme catalyzing the sequential oxidation of hypoxanthine to xanthine, and xanthine to uric acid in purine catabolism. - Each enzyme monomer contains one Molybdenum (Mo) atom coordinated as a molybdopterin cofactor, two distinct $[2\text{Fe}-2\text{S}]$ iron-sulfur ferredoxin centers, and one FAD prosthetic group. - Allopurinol (a suicide substrate) coordinates to the molybdenum catalytic center to treat hyperuricemia/gout. Step 3: Final Answer:
Thus, Xanthine oxidase contains Molybdenum, corresponding to option (D).
