Creative Enzymes enjoys an outstanding reputation due to the meticulous services and rigorous attitude for every testing. The best performed facilities allows highly precise measurement with low variations. Creative Enzymes continuously improves the experimental skills over the past few years, and our method for xanthine oxidase assay guarantees accuracy and reliability.

In mammals, there are two forms of xanthine oxidoreductase (XOR), both belonging to the molybdenum family and catalyzing the hydroxylation of hypoxanthine to xanthine as well as xanthine to uric acid. These two forms of proteins share one same gene. Normally, the enzyme exists in a dehydrogenase form (xanthine dehydrogenase, EC 1.17.1.4) but can be readily converted to its oxidase form, xanthine oxidase, by oxidation of sulfhydryl residues or limited proteolysis. The xanthine oxidase exclusively uses O₂ as the oxidizing reagent, which differs from the ability to use both NAD⁺ and O₂ of xanthine dehydrogenase. During the catalysis reactions, FAD is needed as a cofactor.

In organisms, this enzyme participates in the vital metabolism progress, the purine degradation pathway. The rare genetic disorder xanthinuria is caused by the lack of xanthine oxidase activity, which leads to high concentration of xanthine in blood and urine. Patients with this deficient suffer health problem such as renal failure. The enzyme concentration and activity variations in the body may suggest diseases. For example, the increased activity is found in serum and lungs during influenza A infection, and the liver damage can be determined according to the released xanthine oxidase in the blood. Nowadays, the enzyme has become a target of drugs against gout and hyperuricemia. In addition, xanthine oxidase is also involved in cardiovascular health and oxidative eye injury. To better understand the relationship between the enzyme and diseases, scientists set up a series of studies targeted at xanthine oxidase. Proper assay methods will save precious times for these studies. To this end, Creative Enzymes offers reliable assay methods to satisfy all your demands.

Figure: The structure of xanthine oxidase with 2-hydroxy-6-methylpurine from bovine.
Reference: Pauff, J.M. et al. J.Biol.Chem. 2008 283: 4818-4824.

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