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Literature summary extracted from

  • Geeganage, S.; Frey, P.A.
    Galactose-1-phosphate uridylyltransferase: kinetics of formation and reaction of uridylyl-enzyme intermediate in wild-type and specifically mutated uridylyltransferases (2002), Methods Enzymol., 354, 134-148.
    View publication on PubMed

Protein Variants

EC Number Protein Variants Comment Organism
2.7.7.12 C160A
-
 Escherichia coli
2.7.7.12 Q168G site-directed mutagenesis, reduced activity Escherichia coli
2.7.7.12 Q168H site-directed mutagenesis, reduced activity Escherichia coli
2.7.7.12 Q168N
-
 Escherichia coli
2.7.7.12 Q168R site-directed mutagenesis, 270000fold reduced activity compared to wild-type, i.e. nearly no remaining activity, mutant active sites can be uridylated by 65%, with very slow deuridylylation, compared to 100% for the wild-type, reduced metal content Escherichia coli
2.7.7.12 Q168R in humans galactosemia causing mutation, used as a model in bacterial system, 30000fold loss of activity, 28% reduced metal ion content Escherichia coli
2.7.7.12 S161A
-
 Escherichia coli

Inhibitors

EC Number Inhibitors Comment Organism Structure
2.7.7.12 D-galactose galactosemia, disease caused by genetic disorder, is characterized by a galactose sensitivity Homo sapiens

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
2.7.7.12 additional information
-
 additional information
-
 Homo sapiens
2.7.7.12 additional information
-
 additional information kinetics at 4°C, wild-type and mutants Escherichia coli
2.7.7.12 0.072
-
 UDP-glucose recombinant mutant C160A, pH 8.5, 27°C Escherichia coli
2.7.7.12 0.082
-
 UDP-glucose recombinant mutant C160A, pH 8.5, 27°C Escherichia coli
2.7.7.12 0.125
-
 alpha-D-galactose 1-phosphate recombinant mutant C160A, pH 8.5, 27°C Escherichia coli
2.7.7.12 0.2
-
 UDP-glucose
-
 Homo sapiens
2.7.7.12 0.2
-
 UDP-glucose recombinant mutant Q168N, pH 8.5, 27°C Escherichia coli
2.7.7.12 0.2
-
 UDP-glucose recombinant wild-type, pH 8.5, 27°C Escherichia coli
2.7.7.12 0.223
-
 alpha-D-galactose 1-phosphate recombinant mutant S161A, pH 8.5, 27°C Escherichia coli
2.7.7.12 0.3
-
 alpha-D-galactose 1-phosphate recombinant mutant Q168N, pH 8.5, 27°C Escherichia coli
2.7.7.12 0.3
-
 alpha-D-galactose 1-phosphate recombinant wild-type, pH 8.5, 27°C Escherichia coli

Metals/Ions

EC Number Metals/Ions Comment Organism Structure
2.7.7.12 Fe2+ can be replaced by other metal ions Escherichia coli
2.7.7.12 Fe2+ not essential Escherichia coli
2.7.7.12 Fe2+ coordinated in a square pyramidal geometry with His296, His298, and Glu182 in a bidentate coordination providing the base ligands and His281 providing the axial ligand Escherichia coli
2.7.7.12 Zn2+ required Escherichia coli
2.7.7.12 Zn2+ can be replaced by other metal ions Escherichia coli
2.7.7.12 Zn2+ coordinated in a tetrahedral geometry by Cys52, Cys55, His115, and His164 Escherichia coli

Molecular Weight [Da]

EC Number Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
2.7.7.12 79290
-
 amino acid sequence determination Escherichia coli

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2.7.7.12 UDP-glucose + alpha-D-galactose 1-phosphate Escherichia coli
-
 alpha-D-glucose 1-phosphate + UDP-galactose
-
 r
2.7.7.12 UDP-glucose + alpha-D-galactose 1-phosphate Homo sapiens
-
 alpha-D-glucose 1-phosphate + UDP-galactose
-
 r

Organism

EC Number Organism UniProt Comment Textmining
2.7.7.12 Escherichia coli
-
-
-
2.7.7.12 Homo sapiens
-
-
-

Reaction

EC Number Reaction Comment Organism Reaction ID
2.7.7.12 UDP-alpha-D-glucose + alpha-D-galactose 1-phosphate = alpha-D-glucose 1-phosphate + UDP-alpha-D-galactose Gln168 engages hydrogen bonding with the phosphoryl oxygen of the UMP moiety in the covalently formed reaction intermediate UMP-enzyme, UMP is bound to His166 Escherichia coli
a
2.7.7.12 UDP-alpha-D-glucose + alpha-D-galactose 1-phosphate = alpha-D-glucose 1-phosphate + UDP-alpha-D-galactose ping pong bi bi kinetic model Escherichia coli
a
2.7.7.12 UDP-alpha-D-glucose + alpha-D-galactose 1-phosphate = alpha-D-glucose 1-phosphate + UDP-alpha-D-galactose active site triad: His164, His165, and His166, with His166 as nulceophilic catalyst, highly conserved Escherichia coli
a
2.7.7.12 UDP-alpha-D-glucose + alpha-D-galactose 1-phosphate = alpha-D-glucose 1-phosphate + UDP-alpha-D-galactose active site nucleophil H166 Escherichia coli
a
2.7.7.12 UDP-alpha-D-glucose + alpha-D-galactose 1-phosphate = alpha-D-glucose 1-phosphate + UDP-alpha-D-galactose active site nucleophil H166 Homo sapiens
a
2.7.7.12 UDP-alpha-D-glucose + alpha-D-galactose 1-phosphate = alpha-D-glucose 1-phosphate + UDP-alpha-D-galactose formation of a stable nucleotidylated histidine intermediate Escherichia coli
a
2.7.7.12 UDP-alpha-D-glucose + alpha-D-galactose 1-phosphate = alpha-D-glucose 1-phosphate + UDP-alpha-D-galactose active site: C160SNPHP165 Escherichia coli
a
2.7.7.12 UDP-alpha-D-glucose + alpha-D-galactose 1-phosphate = alpha-D-glucose 1-phosphate + UDP-alpha-D-galactose active site structure, enzyme complexed with UDP-galactose Escherichia coli
a

Specific Activity [micromol/min/mg]

EC Number Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
2.7.7.12 0.00093
-
 recombinant mutant S161A, cell extract Escherichia coli
2.7.7.12 0.023
-
 purified recombinant mutant S161A Escherichia coli
2.7.7.12 0.1
-
 recombinant mutant Q168G and Q168H, cell extract Escherichia coli
2.7.7.12 0.19
-
 recombinant mutant Q168N, cell extract Escherichia coli
2.7.7.12 3.4
-
 purified recombinant mutant Q168N Escherichia coli
2.7.7.12 9.9
-
 recombinant mutant C160A, cell extract Escherichia coli
2.7.7.12 14.9
-
 recombinant mutant C160S, cell extract Escherichia coli
2.7.7.12 16.3
-
 recombinant wild-type, cell extract Escherichia coli
2.7.7.12 79.5
-
 purified recombinant mutant C160A Escherichia coli
2.7.7.12 180
-
 purified recombinant wild-type enzyme Escherichia coli

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2.7.7.12 UDP-glucose + alpha-D-galactose 1-phosphate
-
 Escherichia coli alpha-D-glucose 1-phosphate + UDP-galactose
-
 r
2.7.7.12 UDP-glucose + alpha-D-galactose 1-phosphate
-
 Homo sapiens alpha-D-glucose 1-phosphate + UDP-galactose
-
 r
2.7.7.12 UDP-glucose + alpha-D-galactose 1-phosphate formation of a covalent uridylyl-enzyme intermediate, i.e. UMP-enzyme Escherichia coli alpha-D-glucose 1-phosphate + UDP-galactose
-
 r
2.7.7.12 UDP-glucose + imidazole wild-type, 800fold reduced activity compared to normal reaction intermediate uridylyl-enzyme as substrate, pH-dependent Escherichia coli uridine 5'-phosphoimidazole + alpha-D-glucose 1-phosphate
-
 r

Subunits

EC Number Subunits Comment Organism
2.7.7.12 More
-
 Homo sapiens
2.7.7.12 More dimeric status is essential for activity Escherichia coli

Synonyms

EC Number Synonyms Comment Organism
2.7.7.12 GALT
-
 Escherichia coli

Turnover Number [1/s]

EC Number Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
2.7.7.12 0.0533
-
 alpha-D-galactose 1-phosphate recombinant mutant S161A, forward reaction, pH 8.5, 27°C Escherichia coli
2.7.7.12 19
-
 alpha-D-galactose 1-phosphate recombinant mutant Q168N, forward reaction, pH 8.5, 27°C Escherichia coli
2.7.7.12 265
-
 alpha-D-galactose 1-phosphate recombinant mutant C160A, forward reaction, pH 8.5, 27°C Escherichia coli
2.7.7.12 780
-
 alpha-D-galactose 1-phosphate recombinant wild-type, forward reaction, pH 8.5, 27°C Escherichia coli