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Literature summary extracted from

  • Pacheco, B.; Maccarana, M.; Goodlett, D.R.; Malmstroem, A.; Malmstroem, L.
    Identification of the active site of DS-epimerase 1 and requirement of N-glycosylation for enzyme function (2009), J. Biol. Chem., 284, 1741-1747.
    View publication on PubMed

Cloned(Commentary)

EC Number Cloned (Comment) Organism
5.1.3.19 expression of wild-type and mutant enzymes in HEK-293 cells Homo sapiens

Protein Variants

EC Number Protein Variants Comment Organism
5.1.3.19 H205A site-directed mutagenesis of the catalytic site residue, the mutant shows complete loss of epimerase activity Homo sapiens
5.1.3.19 H450A site-directed mutagenesis of the catalytic site residue, the mutant shows complete loss of epimerase activity Homo sapiens
5.1.3.19 N183S site-directed mutagenesis of an N-glycosylation site in DS-epi1 altering reaction kinetics Homo sapiens
5.1.3.19 N336S site-directed mutagenesis of an N-glycosylation site in DS-epi1 altering reaction kinetics and reducing the activity 13fold Homo sapiens
5.1.3.19 N642S site-directed mutagenesis of an N-glycosylation site in DS-epi1 altering reaction kinetics Homo sapiens
5.1.3.19 N648S site-directed mutagenesis of an N-glycosylation site in DS-epi1 altering reaction kinetics and reducing the activity 43fold Homo sapiens
5.1.3.19 Y261A site-directed mutagenesis of the catalytic site residue, the mutant shows complete loss of epimerase activity Homo sapiens

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
5.1.3.19 0.0049
-
 D-glucuronate pH 5.5, 37°C, recombinant mutant N648S Homo sapiens
5.1.3.19 0.014
-
 D-glucuronate pH 5.5, 37°C, recombinant mutant N336S Homo sapiens
5.1.3.19 0.016
-
 D-glucuronate pH 5.5, 37°C, recombinant mutant N183S Homo sapiens
5.1.3.19 0.016
-
 D-glucuronate pH 5.5, 37°C, recombinant mutant N642S Homo sapiens
5.1.3.19 0.024
-
 D-glucuronate ph 5.5, 37°C, recombinant wild-type enzyme Homo sapiens

Organism

EC Number Organism UniProt Comment Textmining
5.1.3.19 Homo sapiens Q9UL01
-
-

Posttranslational Modification

EC Number Posttranslational Modification Comment Organism
5.1.3.19 glycoprotein proper N-glycosylation of DS-epimerase 1 is required for enzyme activity Homo sapiens

Reaction

EC Number Reaction Comment Organism Reaction ID
5.1.3.19 Chondroitin D-glucuronate = dermatan L-iduronate His-450 functions as a general base abstracting the C5 proton from glucuronic acid. Subsequent cleavage of the glycosidic linkage by Tyr-261 generates a 4,5-unsaturated hexuronic intermediate, which is protonated at the C5 carbon by His-205 from the side of the sugar plane opposite to the side of previous proton abstraction. Concomitant recreation of the glycosidic linkage ends the reaction, generating iduronic acid, proposed molecular mechanism of epimerization, overview Homo sapiens
a

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
5.1.3.19 D-glucuronate
-
 Homo sapiens L-iduronate
-
 ?
5.1.3.19 additional information identification of the catalytic site, and of three putative catalytic residues in DS-epimerase 1, His205, Tyr261, and His450, by tertiary structure modeling and amino acid conservation to heparinase II Homo sapiens ?
-
 ?

Synonyms

EC Number Synonyms Comment Organism
5.1.3.19 DS-epimerase 1
-
 Homo sapiens

Temperature Optimum [°C]

EC Number Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
5.1.3.19 37
-
 assay at Homo sapiens

pH Optimum

EC Number pH Optimum Minimum pH Optimum Maximum Comment Organism
5.1.3.19 5.5
-
 assay at Homo sapiens