3BDJ:
reference: Mechanism of inhibition of xanthine oxidoreductase by allopurinol: crystal structure of reduced bovine milk xanthine oxidoreductase bound with oxipurinol., Okamoto K, Eger BT, Nishino T, Pai EF, Nishino T, Nucleosides Nucleotides Nucleic Acids. 2008 Jun;27(6):888-93. PMID: 18600558

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