Catalysis of the direct transfer of oxygen from nicotinamide N-oxide to xanthine by xanthine oxidase.
D000818:Animals; D002384:Catalysis; D008099:Liver / Q000201:enzymology; D008892:Milk / Q000201:enzymology; D009536:Niacinamide; D010087:Oxides; D010100:Oxygen; D010103:Oxygen Isotopes; D014527:Uric Acid; D014969:Xanthine Oxidase
D010087:Oxides; D010103:Oxygen Isotopes; D009536:Niacinamide; D014527:Uric Acid; D014969:Xanthine Oxidase; D010100:Oxygen