Information on EC 5.1.3.B1 - galactose 1-epimerase

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

EC NUMBER
COMMENTARY hide
5.1.3.B1
preliminary BRENDA-supplied EC number
RECOMMENDED NAME
GeneOntology No.
galactose 1-epimerase
-
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
alpha-D-galactose = beta-D-galactose
show the reaction diagram
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
epimerization
-
-
SYSTEMATIC NAME
IUBMB Comments
D-galactose 1-epimerase
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CAS REGISTRY NUMBER
COMMENTARY hide
182938-11-0
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
-
-
Manually annotated by BRENDA team
anamorph Trichoderma reesei
-
-
Manually annotated by BRENDA team
gene galM
D1TQG1
UniProt
Manually annotated by BRENDA team
gene galM
D1TQG1
UniProt
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
evolution
metabolism
physiological function
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
alpha-D-Fucose
beta-D-Fucose
show the reaction diagram
-
-
-
-
?
alpha-D-Galactose
beta-D-Galactose
show the reaction diagram
alpha-D-Glucose
beta-D-Glucose
show the reaction diagram
alpha-D-quinovose
beta-D-quinovose
show the reaction diagram
-
-
-
-
?
alpha-D-Xylose
beta-D-Xylose
show the reaction diagram
-
-
-
-
?
alpha-L-Arabinose
beta-L-Arabinose
show the reaction diagram
-
-
-
-
?
additional information
?
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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
alpha-D-Galactose
beta-D-Galactose
show the reaction diagram
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
additional information
-
no oxidoreduction cofactor
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METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
-
no metal ion found
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
diethyldicarbonate
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complete loss of activity, galactose partly saves
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
25
alpha-D-Fucose
-
pH 7.6, 25C
4 - 52
alpha-D-galactose
17 - 120
alpha-D-glucose
37
alpha-D-quinovose
-
pH 7.6, 25C
21 - 86
alpha-D-xylose
19 - 170
alpha-L-arabinose
additional information
additional information
-
steady-state kinetics of the epimerase reaction, recombinant enzyme
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TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
1700
alpha-D-Fucose
Lactococcus lactis
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pH 7.6, 25C
50 - 18400
alpha-D-galactose
2.1 - 22000
alpha-D-glucose
490
alpha-D-quinovose
Lactococcus lactis
-
pH 7.6, 25C
1 - 410
alpha-D-xylose
9 - 5500
alpha-L-arabinose
additional information
additional information
Escherichia coli
P0A9C3
turnover number is not dependent on pH-value
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SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
-
galactose is the preferred substrate, overview, coupled assay using glucose/galactose dehydrogenase from Thermoplasma acidophilum specific for the beta-forms of D-glucose and D-galactose, and requiring NADP+ as a cofactor
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pI VALUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5
-
isoform aep1, calculated
5.3
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isoform aep2, calculated
6.4
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isoform aep3, calculated
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
-
isoform aep3, predicted gene location, no galactomutarotase activity present in mycelia, cell walls, or the extracellular medium during growth on lactose
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Manually annotated by BRENDA team
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isoform aep1, predicted gene location, there is no galactomutarotase activity present in Hypocrea jecorina when growing on lactose; isoform aep2, predicted gene location, there is no galactomutarotase activity present in Hypocrea jecorina when growing on lactose
Manually annotated by BRENDA team
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
33588
-
x * 33588, isoform aep1, calculated
34000
-
recombinant His-tagged enzyme, gel filtration
37075
-
x * 37075, isoform aep2, calculated
42380
-
x * 42380, isoform aep3, calculated
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
?
-
x * 33588, isoform aep1, calculated; x * 37075, isoform aep2, calculated; x * 42380, isoform aep3, calculated
monomer
additional information
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
both apoform and in complex with beta-D-galactose, comparison with enzyme from Lactococcus lactis and Caenorhabditis elegans
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both apo-form and in complex with alpha,beta-D-galactose
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in complex with D-glucose, D-fucose, D-quinovose, L-arabinose, or D-xylose
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mutants H96N, H170N, D243N, D243A, E304Q, E304A, complexed with either D-glucose or D-galactose
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in complex with NAD+, UDP-glucose, and beta-D-galactose
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purified recombinant His-tagged enzyme, hanging-drop vapour-diffusion method, 0.003 ml of 10 mg/ml protein in 15-25% PEG 8000, 0.1 M Na citrate, pH 5.5, and 0.2-0.5 mM NaCl for monoclinic crystals, or in 1.5-2 M ammonium sulfate, 25 mM Mg formate, 0.1 M Na cacodylate, pH 5.5, for orthorhombic crystals, cocrystallization of YeaD with ligands glucose, galactose, mannose, fructose, fucose, xylose, lyxose, lactose, maltose, sucrose and glucose 6-phosphate, incubation at 4C for 12 h in a 1:10 molar ratio, X-ray diffraction structure determination and analysis the orthorhombic form at 1.9 A resolution and in the monoclinic form at 2.5 A resolution
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TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
27
-
pH 6.0, full activity for at least 4.8 h
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
recombinant His-tagged enzyme from Escherichia coli strain BL21(DE3) by nickel affinity chromatography
-
recombinant His6-tagged enzyme from Escherichia coli strain MG1655
D1TQG1
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
efficient stereospecific enzymatic synthesis of L-[15N]-valine, L-[15N]-leucine, L-[15N]-norvaline, L-[15N]-norleucine and L-[15N]-isoleucine from the corresponding alpha-keto acids by coupling the reactions catalysed by leucine dehydrogenase and glucose dehydrogenase/galactose mutarotase. Giving high yields of L-amino acids, the procedure is economical and easy to perform and to monitor at a synthetically useful scale of 1-10 g. Substrates alpha-ketoisovalerate, alpha-ketoisocaproate, alpha-ketovalerate, alpha-ketocaproateand alpha-keto-beta-methylvalerate are converted to products L-valine, L-leucine, L-norvaline, L-isoleucine with yields of 90%, 92.5%, 92%, 80%, and 95%, respectively
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expression in Escherichia coli
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expression of the C-terminal galactose mutarotase part of Gal10 in Hypocrea jecorina
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from genomic DNA
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gene galM, DNA and amino acid sequence determination and analysis, sequence comparisons, transcription of the galETK operon is initiated from a single promoter, recombinant expression of His6-tagged enzyme in Escherichia coli strain MG1655
D1TQG1
gene yeaD, expression of the His-tagged enzyme in Escherichia coli strain BL21(DE3)
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
H104Q
-
about 600fold increase in Km-value
H175N
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no enzymic activity detected
D243A
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drastic decrease in activity
D243N
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decrease in kcat-value, increase in Km-value
E304A
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no enzymic activity
E304Q
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no enzymic activity
H170N
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no enzymic activity
H96N
-
large decrease in kcat-value
additional information