2E1Q:
reference: Human xanthine oxidase changes its substrate specificity to aldehyde oxidase type upon mutation of amino acid residues in the active site: roles of active site residues in binding and activation of purine substrate., Yamaguchi Y, Matsumura T, Ichida K, Okamoto K, Nishino T, J Biochem (Tokyo). 2007 Apr;141(4):513-24. Epub 2007 Feb 14. PMID: 17301077

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