Literature summary for 1.17.1.4 extracted from

Zarepour, M.; Kaspari, K.; Stagge, S.; Rethmeier, R.; Mendel, R.R.; Bittner, F.
Xanthine dehydrogenase AtXDH1 from Arabidopsis thaliana is a potent producer of superoxide anions via its NADH oxidase activity (2009), Plant Mol. Biol., 72, 301-310.

Search for more literature for 1.17.1.4

Activating Compound

Activating Compound	Comment	Organism	Structure
sulfide/dithionite	treatment increases the specific activity of AtXDH1	Arabidopsis thaliana

Cloned(Commentary)

Cloned (Comment)	Organism
expression of His-tagged wild-type and mutant XDH1 variants in Pichia pastoris strain KM71	Arabidopsis thaliana
expression of His-tagged XDH1 in Pichia pastoris	Arabidopsis thaliana

Protein Variants

Protein Variants	Comment	Organism
E1297A	site-directed mutagenis	Arabidopsis thaliana
E831A	site-directed mutagenis	Arabidopsis thaliana
R909A	site-directed mutagenis	Arabidopsis thaliana
W364A	site-directed mutagenis	Arabidopsis thaliana
Y421A	site-directed mutagenis	Arabidopsis thaliana

Inhibitors

Inhibitors	Comment	Organism	Structure
allopurinol	-	Arabidopsis thaliana
additional information	NAD+ inhibits NADH-dependent superoxide formation of AtXDH1	Arabidopsis thaliana
NADH	suppresses NAD+-dependent xanthine oxidation	Arabidopsis thaliana

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Fe	a molybdenum-iron-flavoenzyme	Arabidopsis thaliana
Iron	a molybdenum-iron-flavoenzyme, contains [2Fe-2S] centers	Arabidopsis thaliana
Mo	a molybdenum-iron-flavoenzyme	Arabidopsis thaliana
Molybdenum	a molybdenum-iron-flavo enzyme, which contains a C-terminal molybdenum cofactor-binding domain of 85 kDa	Arabidopsis thaliana

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
hypoxanthine + NAD+ + H2O	Arabidopsis thaliana	-	xanthine + NADH + H+	-	?
additional information	Arabidopsis thaliana	XDH can be converted into XO, EC 1.17.3.2, either reversibly by oxidation of the sulfhydryl groups of two conserved cysteine residues. Under physiological conditions the XDH form appears to dominate with 80% over the XO form with 20%	?	-	?
xanthine + NAD+ + H2O	Arabidopsis thaliana	-	urate + NADH + H+	-	?

Organism

Organism	UniProt	Comment	Textmining
Arabidopsis thaliana	-	-	-
Arabidopsis thaliana	Q8GUQ8	-	-

Posttranslational Modification

Posttranslational Modification	Comment	Organism
flavoprotein	-	Arabidopsis thaliana

Purification (Commentary)

Purification (Comment)	Organism
recombinant His-tagged wild-type and mutant XDH1 variants from Pichia pastoris strain KM71 by nickel affinity chromatography and anion exchange chromatography	Arabidopsis thaliana
recombinant His-tagged XDH1 from Pichia pastoris by nickel affinity and anion exchange chromatography	Arabidopsis thaliana

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
0.044	-	purified recombinant enzyme, substrate xanthine, pH 8.0	Arabidopsis thaliana
0.65	-	purified recombinant enzyme, pH 8.0, 25°C	Arabidopsis thaliana
0.702	-	purified recombinant enzyme, substrate NADH, pH 6.6	Arabidopsis thaliana
1.712	-	purified recombinant enzyme, in presence of sulfide/dithionite	Arabidopsis thaliana

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
hypoxanthine + NAD+ + H2O	-	Arabidopsis thaliana	xanthine + NADH + H+	-	?
additional information	XDH can be converted into XO, EC 1.17.3.2, either reversibly by oxidation of the sulfhydryl groups of two conserved cysteine residues. Under physiological conditions the XDH form appears to dominate with 80% over the XO form with 20%	Arabidopsis thaliana	?	-	?
additional information	AtXDH1 is capable of oxidizing NADH with concomitant formation of NAD+ and superoxide, the specific activity of recombinant AtXDH1 with NADH as substrate is about 15times higher than the activity with xanthine accompanied by a doubling in superoxide production and is dependent on sulfurated molybdenum cofactor, overview. FAD is crucial for NADH-based superoxide formation of AtXDH1, whereas the molybdenum cofactor has only little or no influence on the activity, residues E831, R909, E1297, W364, and Y421 are involved	Arabidopsis thaliana	?	-	?
additional information	by an alternative activity, AtXDH1 is capable of oxidizing NADH with concomitant formation of NAD+ and superoxide. In comparison to the specific activity with xanthine as substrate, the specific activity of recombinant AtXDH1 with NADH as substrate is about 15times higher. Each sub-activity is determined by specific conditions such as the availability of substrates and co-substrates, which allows regulation of superoxide production by AtXDH1	Arabidopsis thaliana	?	-	?
xanthine + NAD+ + H2O	-	Arabidopsis thaliana	urate + NADH + H+	-	?

Subunits

Subunits	Comment	Organism
homodimer	composed of two identical subunits of about 145 kDa, each being subdivided into three domains: a N-terminal iron-sulfur-binding domain of 20 kDa, a 40 kDa domain harboring a FAD-binding site, and a C-terminal molybdenum cofactor-binding domain of 85 kDa	Arabidopsis thaliana

Synonyms

Synonyms	Comment	Organism
AtXDH1	-	Arabidopsis thaliana
More	mammalian XOR exists in two interconvertible forms, the xanthine dehydrogenase, XDH, form and the xanthine oxidase, XO, form. The primary gene product is XDH, which can be converted into XO	Arabidopsis thaliana
xanthine oxidoreductase	-	Arabidopsis thaliana
XDH1	-	Arabidopsis thaliana
XOR	-	Arabidopsis thaliana

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
25	-	assay at	Arabidopsis thaliana

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
6.6	-	substrate NADH	Arabidopsis thaliana
8	-	assay at	Arabidopsis thaliana
8	-	substrate xanthine	Arabidopsis thaliana

pH Range

pH Minimum	pH Maximum	Comment	Organism
6.6	8	-	Arabidopsis thaliana

Cofactor

Cofactor	Comment	Organism	Structure
FAD	a molybdenum-iron-flavoenzyme	Arabidopsis thaliana
FAD	a molybdenum-iron-flavoenzyme, activity-to-flavin ratio of 8 with xanthine as substrate and NAD+ as final electron acceptor, recombinant enzyme	Arabidopsis thaliana
molybdenum cofactor	C-terminal	Arabidopsis thaliana
additional information	both NAD+ and NADH compete for the same binding site	Arabidopsis thaliana
NAD+	-	Arabidopsis thaliana
NAD+	NAD+ inhibits NADH oxidase activity of AtXDH1	Arabidopsis thaliana
NADH	suppresses NAD+-dependent xanthine oxidation	Arabidopsis thaliana
[2Fe-2S] cluster	two N-terminal non-identical iron-sulfur clusters of the [2Fe-2S]-type	Arabidopsis thaliana

General Information

General Information	Comment	Organism
additional information	mammalian XOR exists in two interconvertible forms, the xanthine dehydrogenase, XDH, form and the xanthine oxidase, XO, form. The primary gene product is XDH, which can be converted into XO	Arabidopsis thaliana
physiological function	xanthine oxidoreductase is a ubiquitous molybdenum-iron-flavo enzyme with a central role in purine catabolism where it catalyzes the oxidation of hypoxanthine to xanthine and of xanthine to uric acid	Arabidopsis thaliana
physiological function	AtXDH1 is a key enzyme in purine degradation where it oxidizes hypoxanthine to xanthine and xanthine to uric acid	Arabidopsis thaliana

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Release 2023.1 (January 2023)