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Literature summary for 1.17.3.2 extracted from

  • Yamaguchi, Y.; Matsumura, T.; Ichida, K.; Okamoto, K.; Nishino, T.
    Human Xanthine oxidase changes its substrate specificity to aldehyde oxidase type upon mutation of amino acid residues in the active site: roles of active site residues in binding and activation of purine substrate (2007), J. Biochem., 141, 513-524.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expression of wild-type and mtant enzymes in Escherichia coli strain JM109 Homo sapiens

Crystallization (Commentary)

Crystallization (Comment) Organism
purified recombinant mutant E308V, 15mg/ml protein in 5 mM Tris, pH 8.5, containing 1mM sodium salicylate and 0.1mM EDTA, incubation with 5 mM dithiothreitol for 1 h at room temperature, aliquots of 0.005 ml protein solution are mixed with 0.005 ml of 100 mM sodium citrate, pH 5.0, containing 8-11% polyethylene glycol 8000, 5 mM DTT, 1 mM sodium salicylate, 0.1 mM EDTA, and placed on siliconized glass plates, 7 days at 20°C, X-ray diffraction structure determination and analysis at 2.6 A resolution Homo sapiens

Protein Variants

Protein Variants Comment Organism
E308V site-directed mutagenesis, mutant molybdopterin domain structure, overview, the xanthine oxidase changes its substrate specificity to aldehyde oxidase type upon mutation of amino acid residues in the active site, the E803V mutation almost completely abrogates the activity towards hypoxanthine as a substrate, but the decrease in activity towards purine substrate is not due to large conformational change in the mutant enzyme Homo sapiens
R881M site-directed mutagenesis, the xanthine oxidase changes its substrate specificity to aldehyde oxidase type upon mutation of amino acid residues in the active site, the R881M mutant lacks activity towards xanthine, but retaines slight activity towards hypoxanthine Homo sapiens

Inhibitors

Inhibitors Comment Organism Structure
allopurinol
-
Homo sapiens

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
additional information steady-state kinetics analysis of wild-type and mutant enzymes with hypoxanthine of xanthine, and of mutant enzymes with benzaldehyde or 4-(dimethyamino)cinnamaldehyde as aldehyde oxidase substrates, overview Homo sapiens
0.0017
-
hypoxanthine pH 8.5, 25°C, recombinant wild-type enzyme Homo sapiens
0.0088
-
xanthine pH 8.5, 25°C, recombinant wild-type enzyme Homo sapiens
0.021
-
hypoxanthine pH 8.5, 25°C, recombinant mutant R881M Homo sapiens
0.072
-
xanthine pH 8.5, 25°C, recombinant mutant E308V Homo sapiens

Metals/Ions

Metals/Ions Comment Organism Structure
Molybdenum molybdopterin domain structure of enzyme mutant E308V, overview Homo sapiens

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
hypoxanthine + 2 H2O + 2 O2 Homo sapiens
-
urate + 2 H2O2
-
?
xanthine + H2O + O2 Homo sapiens roles of active site residues E308 and R881 in binding and activation of purine substrate, overview urate + H2O2
-
?

Organism

Organism UniProt Comment Textmining
Homo sapiens
-
-
-

Purification (Commentary)

Purification (Comment) Organism
recombinant wild-type and mutant enzymes from Escherichia coli strain JM109 by anion exchange and hydroxyapatite chromatography, ultrafiltration, and gel filtration Homo sapiens

Reaction

Reaction Comment Organism Reaction ID
xanthine + H2O + O2 = urate + H2O2 hydrogen-bonding arrangement of the substrate-bound complex at the active site, and proposed mechanism of the purine oxidation reaction by XOR Homo sapiens

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
hypoxanthine + 2 H2O + 2 O2
-
Homo sapiens urate + 2 H2O2
-
?
xanthine + H2O + O2
-
Homo sapiens urate + H2O2
-
?
xanthine + H2O + O2 roles of active site residues E308 and R881 in binding and activation of purine substrate, overview Homo sapiens urate + H2O2
-
?

Synonyms

Synonyms Comment Organism
xanthine oxidoreductase
-
Homo sapiens
XOR
-
Homo sapiens

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
25
-
assay at Homo sapiens

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.33
-
hypoxanthine pH 8.5, 25°C, recombinant mutant R881M Homo sapiens
1.35
-
xanthine pH 8.5, 25°C, recombinant mutant E308V Homo sapiens
18.3
-
xanthine pH 8.5, 25°C, recombinant wild-type enzyme Homo sapiens
30
-
hypoxanthine pH 8.5, 25°C, recombinant wild-type enzyme Homo sapiens

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8.5
-
assay at Homo sapiens