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Literature summary for 5.1.3.2 extracted from

  • Berger, E.; Arabshahi, A.; Wei, Y.; Schilling, J.F.; Frey, P.A.
    Acid-base catalysis by UDP-galactose 4-epimerase: correlations of kinetically measured acid dissociation constants with thermodynamic values for tyrosine 149 (2001), Biochemistry, 40, 6699-6705.
    View publication on PubMed

Protein Variants

Protein Variants Comment Organism
S124A in contrast to wild-type enzyme the mutant enzyme displays a significant deuterium kinetic isotope effect. Epimerization proceeds with a deuterium kinetic isotope effect of about 2 throughout the pH range 6.3-9.0 Escherichia coli
S124A/Y149F epimerization proceeds at a turnover number that is lower by a factor of 10000000 than that of the wild-type enzyme. This is attributed to the synergistic action of Tyr149 and Ser124 in wild-type enzyme and to the absence of any internal catalysis of hydride transfer in the doubly mutated enzyme. 80% inactivation after 8 min at 50°C compared to 20% inactivation of the wild-type enzyme Escherichia coli
Y149F in contrast to wild-type enzyme the mutant enzyme displays a significant deuterium kinetic isotope effect. At pH there is no significant isotope effect, but at pH 6.3, the isotope effect is 2.2 Escherichia coli

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-

Synonyms

Synonyms Comment Organism
GalE
-
Escherichia coli

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
50
-
wild-type enzyme loses 20% of its activity after 8 min, mutant enzyme S124A/Y149F loses 80% of its activity after 8 min Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
5.5 8.3 activity of the wild-type enzyme is pH-independent in the pH-range of 5.5-9.3 Escherichia coli