Information on EC 1.14.11.48 - xanthine dioxygenase

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The expected taxonomic range for this enzyme is: Aspergillus nidulans

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EC NUMBER
COMMENTARY hide
1.14.11.48
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RECOMMENDED NAME
GeneOntology No.
xanthine dioxygenase
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REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
xanthine + 2-oxoglutarate + O2 = urate + succinate + CO2
show the reaction diagram
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-
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SYSTEMATIC NAME
IUBMB Comments
xanthine,2-oxoglutarate:oxygen oxidoreductase
Requires Fe2+ and L-ascorbate. The enzyme, which was characterized from fungi, is specific for xanthine.
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
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SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
9-methylxanthine + 2-oxoglutarate + O2
?
show the reaction diagram
Q4QZZ9
-
-
-
?
xanthine + 2-oxoadipate + O2
?
show the reaction diagram
-
-
-
-
?
xanthine + 2-oxoglutarate + O2
urate + succinate + CO2
show the reaction diagram
additional information
?
-
-
no activity with pyruvate, 2-oxobutyrate, phenyl pyruvate, and 4-hydroxyphenyl pyruvate
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-
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NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
xanthine + 2-oxoglutarate + O2
urate + succinate + CO2
show the reaction diagram
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-
-
-
?
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METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
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INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
6,8-Dihydroxypurine
Co2+
-
0.04 mM, about 65% inhibition
Cu2+
-
0.04 mM, complete inhibition
Fe2+
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depending on the experimental conditions, Fe2+ concentrations of above 0.025 mM can lead to enzyme inhibition of the recombinant enzyme isolated from Escherichia coli, whereas the enzyme from Aspergillus nidulans is not inhibited at Fe2+ concentrations up to 0.080 mM
Mn2+
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0.04 mM, about 80% inhibition
N-oxalylglycine
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competes with 2-oxoglutarate
NaCl
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0.5 M NaCl increases the Km of 2-oxoglutarate, increases the Km of xanthine and decreased the kcat
Zn2+
-
0.04 mM, complete inhibition
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.16
2-oxoadipate
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25°C, pH 7.4, recombinant enzyme isolated from Escherichia coli
0.031 - 0.059
2-oxoglutarate
0.4 - 1.09
9-methylxanthine
0.045 - 0.554
xanthine
additional information
2-oxoglutarate
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TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
7.6
2-oxoadipate
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25°C, pH 7.4, recombinant enzyme isolated from Escherichia coli
2 - 67
2-oxoglutarate
0.66 - 5.9
9-methylxanthine
3 - 72
xanthine
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kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
340 - 2160
2-oxoglutarate
850 - 9500
9-methylxanthine
70 - 1600
xanthine
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Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.00012
N-oxalylglycine
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pH 7.4, 25°C
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pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6.9
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assay at
7 - 8
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the recombinant enzyme isolated from Escherichia coli exhibits a narrow pH optimum of 7.0-8.0 with pH 7.4 yielding optimal activity for Tris, MOPS, MES, imidazole, and HEPES buffers
7
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enzyme isolated from Aspergillus nidulans
7.4
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assay at
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TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
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SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
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MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
40000
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12 * 40000, SDS-PAGE
500000
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dodecamer, gel filtration
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SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
dodecamer
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12 * 40000, SDS-PAGE
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POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
glycoprotein
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presence of O-glycosylation as well as N-glycosylation
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pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7 - 11
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stable
731289
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STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-80°C, stable for at least 2 months
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4°C, stored in 100 mM Tris buffer (pH 7) containing 300 mM NaCl, 250 mM imidazole, 15% glycerol, and 0.005 mM Fe2+, concentrated enzyme is stable for at least 5 months
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4°C, stored in 100 mM Tris buffer (pH 8.0) containing 300 mM NaCl, 250 mM imidazole, 1 mM EDTA, and 15% glycerol, stable for at least 1 month
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
purified from both the fungal mycelium and recombinant Escherichia coli cells
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wild-type enzyme variants are purified from recombinant Escherichia coli cells
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
overproduction of His6-tagged enzyme in Aspergillus nidulans and Escherichia coli
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wild-type and mutant enzymes
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
C357A
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enhanced activity towards 9-methylxanthine as compared to wild-type enzyme. Mutant enzyme is resistant rto thiol-specific reagents that inactivated wild-type enzyme. Elevated ferroxidase activity in the absence of substrates
D138A
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enhanced activity towards 9-methylxanthine as compared to wild-type enzyme. Significant decrease in Ki(app) for 6,8-dihydroxypurine
D151A
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inactive mutant enzyme
E137A
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enhanced activity towards 9-methylxanthine as compared to wild-type enzyme. Significant decrease in Ki(app) for 6,8-dihydroxypurine
H149A
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inactive mutant enzyme
H340A
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mutant enzyme exhibits 0.17% of the wild-type enzyme activity
K122A
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2fold increase in the Kd of 2-oxoglutarate compared to wild-type enzyme
N358A
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23fold decrease in kcat/Km compared to wild-type enzyme. Significant decrease in Ki(app) for 6,8-dihydroxypurine
Q101A
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elevated ferroxidase activity in the absence of substrates
Q356A
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significant decrease in Ki(app) for 6,8-dihydroxypurine. Elevated ferroxidase activity in the absence of substrates
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LINKS TO OTHER DATABASES (specific for EC-Number 1.14.11.48)
ExplorEnz
ExPASy
KEGG
MetaCyc
SABIO-RK
NCBI: PubMed, Protein, Nucleotide, Structure, Genome, OMIM
IUBMB Enzyme Nomenclature
PROSITE Database of protein families and domains
InterPro (database of protein families, domains and functional sites)