Not available outside of the UK & Ireland.

Analysis Note

Protein determined by biuret

Application

Xanthine Oxidase from bovine milk has been used:as a source for superoxide generationfor the degradation of hypoxanthinefor the detection of reactive oxygen species (ROS) in lipid model by electron spin resonance (ESR) spin trap methodas a constituent of assay mixture in xanthine oxidase inhibition assay

Biochem/physiol Actions

Xanthine Oxidase (XO) belongs to the class of complex metalloflavoproteins. It is produced by oxidation of sulfhydryl residues or by proteolysis of xanthine dehydrogenase (XDH). XO and XDH plays a vital role in the last two steps in the formation of urate. Elevated levels of XO has been observed in the serum of chronic liver disease patients. Therefore, XO can be used as a biomarker for the detection of liver disease.

Xanthine oxidase activity is inhibited by folic acid.

Xanthine oxidase is a molybdenum-containing enzyme that is found in the cytosol, and may be strongly inhibited by flavonoids. It plays a vital role in the metabolism of some drugs, as well as purines and pyrimidines. It is also known to be a biological source of reactive oxygen species.

General description

Formerly E.C. 1.1.3.22

Physical form

Suspension in 2.3 M (NH₄)₂SO₄, 10 mM sodium phosphate buffer, pH 7.8, containing 1 mM EDTA and 1 mM sodium salicylate

Preparation Note

Chromatographically purified

Unit Definition

One unit will convert 1.0 µmole of xanthine to uric acid per min at pH 7.5 at 25 °C. Approx. 50% of the activity is obtained with hypoxanthine as substrate.