Center for Bioinformatics
Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases

Basic Information

Enzyme Number

Official Name

xanthine dehydrogenase

Name from literature

xanthine oxidoreductase

Pathway from literature

purine catabolism

Pathway from KEGG

Nucleotide Metabolism; Purine metabolism; map00230


Human (9606)

Genome localization

2p23.1[7498 ],


Acts on a variety of purines and aldehydes, including hypoxanthine. The enzyme from eukaryotes contains [2Fe-2S], FAD and a molybdenum centre. The animal enzyme can be interconverted to EC, xanthine oxidase (the oxidase form). That from liver exists in vivo mainly in the dehydrogenase form, but can be converted into EC by storage at -20 _degree_C, by treatment with proteolytic agents or organic solvents, or by thiol reagents such as Cu2+, N-ethylmaleimide or 4-mercuribenzoate. The effect of thiol reagents can be reversed by thiols such as 1,4-dithioerythritol. This enzyme can also be converted into EC by EC, enzyme-thiol transhydrogenase (glutathione-disulfide) in the presence of glutathione disulfide. In other animal tissues, the enzyme exists almost entirely as EC, but can be converted into the dehydrogenase form by 1,4-dithioerythritol.

Rate-limiting Description

"Xanthine oxidoreductase (XOR) is the rate-limiting enzyme in purine catabolism occurring in most cell types." (12502743)

Regulatory Information

Regulatory type


key enzyme;

"Xanthine oxido-reductase, a key enzyme of uric acid metabolism was indicated as one of regulatory factors in adipocyte differentiation." (18409529)

transcriptional level;

"Transcriptional regulation of human xanthine dehydrogenase/xanthine oxidase." (9388548#8661045)

post translational modification;

"We observe that gene expression of XDH/XO is regulatory in a cell-specific manner and is markedly affected by inflammatory cytokines, steroids, and physiologic events such as hypoxia. Posttranslational processing is also important in regulating XDH/XO activity." (9788904)


"The NAD+ dependent retinol oxidation catalyzed by xanthine dehydrogenase is strictly dependent on cellular retinol binding proteins and is inhibited by oxypurinol" (18569334)





Gene ontology

Gene ontology

GO:0050660 (F) FAD binding [P47989 ];
GO:0051537 (F) 2 iron, 2 sulfur cluster binding [P47989 ];
GO:0030151 (F) molybdenum ion binding [P47989 ];
GO:0005829 (C) cytosol [P47989 ];
GO:0005506 (F) iron ion binding [P47989 ];
GO:0004855 (F) xanthine oxidase activity [P47989 ];
GO:0009055 (F) electron carrier activity [P47989 ];
GO:0005777 (C) peroxisome [P47989 ];
GO:0004854 (F) xanthine dehydrogenase activity [P47989 ];
GO:0055114 (P) oxidation reduction [P47989 ];

Subcellular localization


peroxisome [P47989 ];

Disease relevance


May contribute to adult respiratory stress syndrome (ARDS) and may potentiate influenza infection through an oxygen metabolite-dependent mechanism [P47989 ];

Defects in XDH are the cause of xanthinuria type 1 (XU1) [MIM:278300]. Xanthinuria is characterized by excretion of very large amounts of xanthine in the urine and a tendency to form xanthine stones. Uric acid is strikingly diminished in serum and urine. XU1 is due to isolated xanthine dehydrogenase. XU1 patients can metabolize allopurinol [P47989 ];


Entrez Gene




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  Last Modified: 2009-03-24  
  Design by Zhao Min