Literature summary for 1.17.3.2 extracted from
Cao, H.; Pauff, J.; Hille, R.
Substrate orientation and the origin of catalytic power in xanthine oxidoreductase (2011), Indian J. Chem., 50A, 355-362.
No PubMed abstract available
Crystallization (Commentary)
Crystallization (Comment) |
Organism |
crystal structure determination and analysis of the enzyme in complex with a variety of substrates and substrate analogues, e.g. with 2-hydroxy-6-methylpurine or hypoxanthine, X-ray diffraction structure analysis at 1.8-3.1 A resolution |
Bos taurus |
Inhibitors
Inhibitors |
Comment |
Organism |
Structure |
alloxanthine |
a mechanism-based inhibitor, binding structure, overview. Inhibition mechanism involves binding to molybdenum, overview |
Bos taurus |
|
Metals/Ions
Metals/Ions |
Comment |
Organism |
Structure |
Fe2+ |
in a [Fe2-S2] domain |
Bos taurus |
|
Molybdenum |
the molybdenum center is a pyranopterin-MoVI-OS-OH. The pyranopterin cofactor is coordinated to the metall via an enedithiolate side chain, coordination geometry, overview |
Bos taurus |
|
additional information |
the molybdenum center is located in a separate subunit from the Fe/S- and flavin-containing parts of the enzyme |
Bos taurus |
|
Molecular Weight [Da]
Molecular Weight [Da] |
Molecular Weight Maximum [Da] |
Comment |
Organism |
295000 |
- |
- |
Bos taurus |
Organism
Organism |
UniProt |
Comment |
Textmining |
Bos taurus |
- |
- |
- |
Reaction
Reaction |
Comment |
Organism |
Reaction ID |
xanthine + H2O + O2 = urate + H2O2 |
reaction mechanism, detailed overview. The reaction is initiated by proton abstraction from the Mo-OH group by Glu1261, the active-site base, followed by nucleophilic attack on the carbon to be hydroxylated, and hydride transfer to the Mo-S double bond. Suitable substrate orientation, overview. Arg880 is involved in stablizing the transition state in the course of nucleophilic attack, overview |
Bos taurus |
|
Substrates and Products (Substrate)
Substrates |
Comment Substrates |
Organism |
Products |
Comment (Products) |
Rev. |
Reac. |
additional information |
role of Glu802 is facilitating the tautomerization of hypoxanthine in the course of hydroxylation by the enzyme, substrate binding structures, overview |
Bos taurus |
? |
- |
? |
|
additional information |
xanthine and lumazine are good substrates, while 2-hydroxy-6-methylpurine is a slow and poor substrate |
Bos taurus |
? |
- |
? |
|
Subunits
Subunits |
Comment |
Organism |
homodimer |
alpha2, with four redox-active centers in each subunit laid out in discretely folding domains, structure, overview |
Bos taurus |
Synonyms
Synonyms |
Comment |
Organism |
xanthine oxidoreductase |
- |
Bos taurus |
Cofactor
Cofactor |
Comment |
Organism |
Structure |
FAD |
- |
Bos taurus |
|
additional information |
the molybdenum center is located in a separate subunit from the Fe/S- and flavin-containing parts of the enzyme |
Bos taurus |
|
General Information
General Information |
Comment |
Organism |
additional information |
active site structure, overview |
Bos taurus |
physiological function |
xanthine oxidase functions not only to hydroxylate xanthine at C-8 to give uric acid, but also hypoxanthine at C-2 to give xanthine in the immediate preceding step of purine catabolism |
Bos taurus |