Information on EC 5.1.3.19 - chondroitin-glucuronate 5-epimerase

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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
5.1.3.19
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RECOMMENDED NAME
GeneOntology No.
chondroitin-glucuronate 5-epimerase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
Chondroitin D-glucuronate = dermatan L-iduronate
show the reaction diagram
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
epimerization
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-
-
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
dermatan sulfate biosynthesis (late stages)
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Glycosaminoglycan biosynthesis - chondroitin sulfate / dermatan sulfate
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Metabolic pathways
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SYSTEMATIC NAME
IUBMB Comments
chondroitin-D-glucuronate 5-epimerase
Not identical with EC 5.1.3.17 heparosan-N-sulfate-glucuronate 5-epimerase.
CAS REGISTRY NUMBER
COMMENTARY hide
70766-66-4
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86417-91-6
identical to EC 6.2.1.26
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
metabolism
the enzyme catalyzes a step in dermatan sulfate and chondroitin sulfate biosynthesis, pathway overview; the enzyme catalyzes a step in dermatan sulfate and chondroitin sulfte biosynthesis, pathway overview
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
Chondroitin D-glucuronate
Dermatan L-iduronate
show the reaction diagram
Chondroitin D-glucuronosyl residues
Chondroitin L-iduronosyl residues
show the reaction diagram
-
-
-
-
D-glucuronate
L-iduronate
show the reaction diagram
D-glucuronic acid
L-iduronic acid
show the reaction diagram
-
-
-
-
?
Dermatan D-glucuronosyl residues
Dermatan L-iduronosyl residues
show the reaction diagram
-
-
-
-
additional information
?
-
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
Chondroitin D-glucuronate
Dermatan L-iduronate
show the reaction diagram
Q8IZU8
-
-
-
?
D-glucuronate
L-iduronate
show the reaction diagram
D-glucuronic acid
L-iduronic acid
show the reaction diagram
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-
-
-
?
additional information
?
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METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
Small proteoglycan core proteins
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may have a role as a modulator of the activity of these enzyme
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0049 - 0.024
D-glucuronate
0.067 - 0.37
glucuronosyl residues
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0.12
glucuronosyl residues in chondroitin
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-
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pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5.6
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6.5
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6.8 - 7.5
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assay at
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
-
-
Manually annotated by BRENDA team
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-
Manually annotated by BRENDA team
additional information
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expression levels of wild-type, heterozygous and homozygous enzyme mutants, overview
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
89000
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mass spectrometry analysis, SDS-PAGE
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
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domain structures of DS-epi1 and DS-epi2, overview
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
glycoprotein
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proper N-glycosylation of DS-epimerase 1 is required for enzyme activity
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
43000-fold from bovine spleen microsomes
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recombinant myc/His-tagged DS-epi1 and FLAG-tagged DS-epi2 partially in HEK-293 cell microsomes
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
cloning and genomic structures of DS-epi1 and DS-epi2, transient functional overexpression of myc/His-tagged DS-epi1 and FLAG-tagged DS-epi2 in HEK-293 cell microsomes
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expression of wild-type and mutant enzymes in HEK-293 cells
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gene DSE, transient expression of wild-type and mutant enzymes in COS-7 cells
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
generation of DS-epi1-null mice, the mutant mice show alterations in the chondroitin/dermatan polysaccharide chains. The numbers of long blocks of adjacent iduronic acids are greatly decreased in skin decorin and biglycan chondroitin/dermatan sulfate, along with a parallel decrease in iduronic-2-O-sulfated-galactosamine-4-O-sulfated structures. Both iduronic acid blocks and iduronic acids surrounded by glucuronic acids are also decreased in versican-derived chains. DS-epi1-deficient mice are smaller than their wild-type littermates but otherwise have no gross macroscopic alterations, DS-epi1-null fibrils have a larger diameter than the wild-type fibrils, phenotypes, overview
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
H205A
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site-directed mutagenesis of the catalytic site residue, the mutant shows complete loss of epimerase activity
H450A
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site-directed mutagenesis of the catalytic site residue, the mutant shows complete loss of epimerase activity
N183S
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site-directed mutagenesis of an N-glycosylation site in DS-epi1 altering reaction kinetics
N336S
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site-directed mutagenesis of an N-glycosylation site in DS-epi1 altering reaction kinetics and reducing the activity 13fold
N642S
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site-directed mutagenesis of an N-glycosylation site in DS-epi1 altering reaction kinetics
N648S
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site-directed mutagenesis of an N-glycosylation site in DS-epi1 altering reaction kinetics and reducing the activity 43fold
S268L
a naturally occuring homozygous DSE mutation c.803C>T in a patient with musculocontractural type of Ehlers-Danlos syndrome, MCEDS. The mutant enzymes shows a loss of activity towards partially desulfated dermatan sulfate, patient-derived fibroblasts also show a significant reduction in epimerase activity
Y261A
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site-directed mutagenesis of the catalytic site residue, the mutant shows complete loss of epimerase activity
additional information
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siRNA gene silencing of DS-epi2 and DS-epi1 in lung HFL-1 fibroblasts
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
analysis
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assay procedure for chondroitin-glucuronate 5-epimerase which is based on the use of a two-phase system for liquid scintillation. 3H2O formed during the reaction, is extracted into an organic phase containing fluorine and isoamyl alcohol, while unreacted pol