Information on EC 1.1.1.325 - sepiapterin reductase (L-threo-7,8-dihydrobiopterin forming)

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The expected taxonomic range for this enzyme is: Bacteria, Eukaryota

EC NUMBER
COMMENTARY hide
1.1.1.325
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RECOMMENDED NAME
GeneOntology No.
sepiapterin reductase (L-threo-7,8-dihydrobiopterin forming)
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REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
L-threo-7,8-dihydrobiopterin + NADP+ = sepiapterin + NADPH + H+
show the reaction diagram
(1)
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L-threo-tetrahydrobiopterin + 2 NADP+ = 6-pyruvoyl-5,6,7,8-tetrahydropterin + 2 NADPH + 2 H+
show the reaction diagram
(2)
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
threo-tetrahydrobiopterin biosynthesis
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Folate biosynthesis
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Metabolic pathways
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SYSTEMATIC NAME
IUBMB Comments
L-threo-7,8-dihydrobiopterin:NADP+ oxidoreductase
This enzyme, isolated from the bacterium Chlorobium tepidum, catalyses the final step in the de novo synthesis of tetrahydrobiopterin from GTP. cf. EC 1.1.1.153, sepiapterin reductase (L-erythro-7,8-dihydrobiopterin forming).
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
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UniProt
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
metabolism
sepiapterin reductase (SPR) catalyzes the final steps of tetrahydrobiopterin (BH4) biosynthesis
physiological function
sepiapterin reductase (SPR) catalyzes the final steps of tetrahydrobiopterin (BH4) biosynthesis. BH4 is an essential cofactor for aromatic acid hydroxylases and nitric oxide synthase. BH4 deficiency causes endothelial dysfunction, such as hypertension, atherosclerosis, diabetes, etc.
additional information
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alignment of amino acid sequences near the N-termini of sepiapterin reductases from various sources, overview
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
6-pyruvoyl-5,6,7,8-tetrahydropterin + 3 NADPH + 3 H+
L-threo-7,8-dihydrobiopterin + 3 NADP+
show the reaction diagram
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?
6-pyruvoyl-5,6,7,8-tetrahydropterin + NADPH + H+
L-threo-7,8-dihydrobiopterin + NADP+
show the reaction diagram
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?
diacetyl + NADPH + H+
? + NADP+
show the reaction diagram
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?
L-threo-7,8-dihydrobiopterin + NADP+
sepiapterin + NADPH + H+
show the reaction diagram
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r
sepiapterin + NADPH + H+
L-threo-7,8-dihydrobiopterin + NADP+
show the reaction diagram
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?
sepiapterin + NADPH + H+
tetrahydrobiopterin + NADP+
show the reaction diagram
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no stereochemic specification in the publication
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?
additional information
?
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the enzyme also shows activity with D-threo-dihydrobiopterin, L-threo-dihydroneopterin, and dihydrotepidopterin, and low activity with L-erythro-dihydrobiopterin
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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
6-pyruvoyl-5,6,7,8-tetrahydropterin + 3 NADPH + 3 H+
L-threo-7,8-dihydrobiopterin + 3 NADP+
show the reaction diagram
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?
6-pyruvoyl-5,6,7,8-tetrahydropterin + NADPH + H+
L-threo-7,8-dihydrobiopterin + NADP+
show the reaction diagram
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?
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
NADPH
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
N-acetyldopamine
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additional information
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N-acetylserotonin and melatonin are no inhibitors
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
4
diacetyl
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pH 8.8, 45°C
0.0062
NADPH
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pH 8.8, 45°C
0.021 - 0.0235
sepiapterin
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
5
NADPH
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pH 8.8, 45°C
5
sepiapterin
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pH 8.8, 45°C
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.4
N-acetyldopamine
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pH 8.8, 45°C
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
4
; recombinant enzyme
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
2.5 - 12
activity range, profile overview, recombinant His-tagged enzyme, over 50% of maximal activity at pH 3.0-11.0
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
20 - 90
activity range, profile overview, recombinant His-tagged enzyme, over 50% of maximal activity at 30-85°C
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
highest expression; larval, high enzyme level
Manually annotated by BRENDA team
additional information
during the development of Musca domestica, the expression of MDSPR in the larvae is higher than other developmental stages
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
26000
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2 * 26000, SDS-PAGE
55000
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gel filtration
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
?
x * 51000, SDS-PAGE, recombinant fusion protein, x * 31494, calculated; x * 51000, soluble recombinant His-tagged enzyme, SDS-PAGE
homodimer
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2 * 26000, SDS-PAGE
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
purified recombinant His-tagged wild-type and selenomethionine-substituted enzymes, hanging drop vapour diffusion method at 18°C, mixing of 0.004 ml of protein solution containing 10 mg/ml in 20 mM Tris-HCl, pH 8.0, by ultrafiltration, with 0.001 ml of reservoir solution containing 0.2 M MgCl2, 0.1 M Tris-HCl, pH 8.5, 34% PEG 400, and 0.2 M guanidine hydrochloride, screening and method optimization, crystals of the wild-type enzyme are soaked in reservoir solution containing 1 mM NADP+ and 1 mM sepiapterin or containing 1 mM NADP+ and 1 mM N-acetylserotonin, respectively, X-ray diffraction structure determination and analysis at 2.1 A resolution
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GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
stability of the purified enzyme disappears in sodium citrate buffer and potassium phosphate buffer for 24 h at 4°C, it increases continuously in Tris-HCl buffer and in glycine/NaOH buffer
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
native enzyme 533fold from cytosol by ammonium sulfate fractionation, anion exchange chromatography, and gel filtration followed by affinity chromatography, another different step of anion exchange chromatography, and ultrafiltration
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recombinant His-tagged enzyme from Escherichia coli strain BL21(DE3)
recombinant His-tagged wild-type and selenomethionine-substituted enzymes from Escherichia coli strain BL21(DE3) by nickel affinity chromatography, ultrafiltration, anion exchange chromatography, and gel filtration
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli; subtractive cDNA library screening, DNA and amino acid sequence determination and analysis, sequence comparisons, phylogenetic tree, recombinant expression of His-tagged enzyme in Escherichia coli strain BL21(DE3)
expression of His-tagged wild-type and selenomethionine-substituted enzymes in Escherichia coli strain BL21(DE3)
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EXPRESSION
ORGANISM
UNIPROT
LITERATURE
infection with Escherichia coli induces the enzyme in Musca domestica larvae, highest after 24 h