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X4500 Sigma

Xanthine Oxidase from bovine milk

Grade III, ammonium sulfate suspension, 1.0-2.0 units/mg protein

Synonym: XOD, Xanthine:oxygen oxidoreductase



Related Categories 1.1.x.x Acting on hydroxyl groups, 1.x.x.x Oxidoreductases, Biochemicals and Reagents, Cell Biology, Enzyme Class Index,
type   Grade III
form   ammonium sulfate suspension
foreign activity   uricase ≤0.1%
storage temp.   2-8°C


Analysis Note

Protein determined by biuret

Biochem/physiol Actions

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.

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.

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

Price and Availability

All labs need water
Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 
Protocols & Articles


Ammonium Sulfate Suspensions - Technical Note

Note that for an ammonium sulfate suspension, most of the enzyme will be in solid form. It is likely that only negligible amounts of enzyme will be in the ammonium sulfate solution.
Keywords: Enzyme activity

Related Content

Enzymes & Proteins

Application Index | Enzyme Index | Substrate Index | Inhibitor Index | Cofactor Index | Lectin Index
Keywords: Cell signaling, Diagnostic, Drug discovery, Molecular biology

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