Xanthine oxidase (XO; EC 220.127.116.11) is an oxidoreductase enzyme that plays an important role in the catabolism of purines in some species, including humans. It catalyzes the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid. Being capable of reducing the production of uric acid in patients suffering from Gout by means of xanthine oxidase inhibition, Febuxostat (TEI 6720, Axon 1175) and Piraxostat (Y-700, Axon 1174) are two important pharmacological tools for the prophylactic treatment of inflammatory arthritis.
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