XANTHINE OXIDASE (XOD) FROM COW MILK

General description

Xanthine Oxidase (XOD) is a metal flavoprotein. It has FAD, molybdenum and iron in the ratio 2:2:8.

Xanthine:oxygen oxidoreductase

Application

Xanthine Oxidase (XOD) has been used in the assessment of XOR-mediated NO production from NDHP and assessment of nitrite-derived NO in liver and purified XOR.

Xanthine Oxidase has been used to study tyrosine nitration.

Biochem/physiol Actions

Xanthine Oxidase (XOD) exhibits a broad substrate specificity including aldehydes, purines and pteridines. Furthermore, this enzyme reduces oxygen to generate superoxide, hydrogen peroxide and reactive oxygen species (ROS). It also reduces nitrite to yield reactive nitrogen species (RNS), such as peroxynitrite and nitric oxide. Owing to its ability to generate RNS and ROS, XOD might play an important role as an antimicrobial agent in the neonatal gut, thereby complementing endogenous enzyme of the intestinal epithelium.

Quality

Contaminants: <0.005% guanase, NP and uricase, each, <0.05% ADA, <0.05% alkaline phosphatase (4-nitrophenyl phosphate as the substrate)
Note: Chromatographically purified.

Sequence

XOD is a dimer. Each subunit contains 1 atom of molybdenum, 2 iron-sulfur centers (non-heme iron, ferredoxin-type) and 1 molecule of FAD.

Unit Definition

One unit (U) xanthine oxidase will produce 1 μmol of uric acid (E_293nm = 12.2 mmol ^-1 x L x cm^-1) from the oxidation of 1 μmol of xanthine in 1 min at 25 °C and pH8.5.

Physical form

Suspension in 3.2 M ammonium sulfate solution, 10 mM EDTA, pH approximately 8

Preparation Note

Activator: O₂
Stabilizers: The substance is stabilized by the addition of EDTA; salicylate is not added.

Other Notes

For life science research only. Not for use in diagnostic procedures.