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Literature summary extracted from

  • Radeghieri, A.; Bonoli, M.; Parmeggiani, F.; Hochkoeppler, A.
    Tyrosine 83 is essential for the activity of E. coli galactoside transacetylase (2007), Biochim. Biophys. Acta, 1774, 243-248.
    View publication on PubMed

Cloned(Commentary)

EC Number Cloned (Comment) Organism
2.3.1.18 gene lacA, overexpression of His6-tagged wild-type and mutant enzymes in Escherichia coli TOP10 cells Escherichia coli
2.3.1.18 into the pTrcHisB vector Escherichia coli

Protein Variants

EC Number Protein Variants Comment Organism
2.3.1.18 Y83F site-directed mutagenesis, the mutant shows highy reduced activity compared to the wild-type enzyme Escherichia coli
2.3.1.18 Y83F tyrosine83 is essential for the activity of galactoside transacetylase Escherichia coli
2.3.1.18 Y83L site-directed mutagenesis, the mutant shows highly reduced activity compared to the wild-type enzyme Escherichia coli
2.3.1.18 Y83L tyrosine83 is essential for the activity of galactoside transacetylase Escherichia coli
2.3.1.18 Y83V site-directed mutagenesis, the mutant shows highly reduced activity compared to the wild-type enzyme Escherichia coli
2.3.1.18 Y83V tyrosine83 is essential for the activity of galactoside transacetylase Escherichia coli

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
2.3.1.18 12
-
 p-nitrophenyl-beta-D-galactopyranoside H155A variant Escherichia coli
2.3.1.18 24.1
-
 4-nitrophenyl-beta-D-galactopyranoside 25°C, mutant Y83L Escherichia coli
2.3.1.18 24.1
-
 p-nitrophenyl-beta-D-galactopyranoside hexahistidine-tagged Y83L mutant Escherichia coli
2.3.1.18 27.2
-
 4-nitrophenyl-beta-D-galactopyranoside 25°C, wild-type enzyme Escherichia coli
2.3.1.18 27.2
-
 p-nitrophenyl-beta-D-galactopyranoside hexahistidine-tagged wild type enzyme Escherichia coli
2.3.1.18 29.5
-
 4-nitrophenyl-beta-D-galactopyranoside 25°C, mutant Y83F Escherichia coli
2.3.1.18 29.5
-
 p-nitrophenyl-beta-D-galactopyranoside hexahistidine-tagged Y83F mutant Escherichia coli
2.3.1.18 60
-
 p-nitrophenyl-beta-D-galactopyranoside wild type enzyme Escherichia coli
2.3.1.18 97
-
 4-nitrophenyl-beta-D-galactopyranoside 25°C, mutant Y83V Escherichia coli
2.3.1.18 97
-
 p-nitrophenyl-beta-D-galactopyranoside hexahistidine-tagged Y83V mutant Escherichia coli
2.3.1.18 629
-
 isopropyl-thio-beta-D-galactopyranoside hexahistidine-tagged wild type enzyme Escherichia coli
2.3.1.18 770
-
 isopropyl-thio-beta-D-galactopyranoside wild type enzyme Escherichia coli
2.3.1.18 1150
-
 isopropyl-thio-beta-D-galactopyranoside hexahistidine-tagged Y83V mutant Escherichia coli
2.3.1.18 2440
-
 isopropyl-thio-beta-D-galactopyranoside hexahistidine-tagged Y83L mutant Escherichia coli
2.3.1.18 2720
-
 isopropyl-thio-beta-D-galactopyranoside hexahistidine-tagged Y83F mutant Escherichia coli

Molecular Weight [Da]

EC Number Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
2.3.1.18 28000
-
 determined by SDS-PAGE and gel filtration, monomer, containing a hexahistidine tag Escherichia coli
2.3.1.18 80000
-
 recombinant enzyme, gel filtration Escherichia coli
2.3.1.18 80000
-
 determined by SDS-PAGE and gel filtration, trimer, containing hexahistidine tags Escherichia coli

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2.3.1.18 acetyl-CoA + a beta-D-galactoside Escherichia coli
-
 CoA + a 6-acetyl-beta-D-galactoside
-
 ?
2.3.1.18 acetyl-CoA + beta-D-galactoside Escherichia coli
-
 CoA + 6-acetyl-beta-D-galactoside
-
 ?

Organism

EC Number Organism UniProt Comment Textmining
2.3.1.18 Escherichia coli
-
-
-
2.3.1.18 Escherichia coli
-
 gene lacA
-

Purification (Commentary)

EC Number Purification (Comment) Organism
2.3.1.18 recombinant His6-tagged wild-type and mutant enzymes by nickel affinity chromatography, ion exchange chromatography, and gel filtration Escherichia coli
2.3.1.18 using a HiTrap metal-chelating affinity chromatography column, a HiTrap desalting, and a Superdex 200 column Escherichia coli

Reaction

EC Number Reaction Comment Organism Reaction ID
2.3.1.18 acetyl-CoA + a beta-D-galactoside = CoA + a 6-acetyl-beta-D-galactoside Tyr83 is essential for enzyme activity Escherichia coli
a

Specific Activity [micromol/min/mg]

EC Number Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
2.3.1.18 additional information
-
-
 Escherichia coli

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2.3.1.18 4-nitrophenyl beta-D-galactopyranoside + acetyl-CoA
-
 Escherichia coli 4-nitrophenyl 6-O-acetyl-beta-D-galactopyranoside + CoA
-
 ?
2.3.1.18 acetyl-CoA + a beta-D-galactoside
-
 Escherichia coli CoA + a 6-acetyl-beta-D-galactoside
-
 ?
2.3.1.18 acetyl-CoA + beta-D-galactoside
-
 Escherichia coli CoA + 6-acetyl-beta-D-galactoside
-
 ?
2.3.1.18 isopropyl-thio-beta-D-galactopyranoside
-
 Escherichia coli ?
-
 ?
2.3.1.18 isopropyl-thio-beta-D-galactopyranoside + acetyl-CoA
-
 Escherichia coli 6-acetyl-isopropyl-thio-beta-D-galactopyranoside + CoA
-
 ?
2.3.1.18 isopropyl-thio-beta-D-galactopyranoside + acetyl-CoA
-
 Escherichia coli isopropyl 6-O-acetyl-1-thio-beta-D-galactopyranoside + CoA
-
 ?
2.3.1.18 p-nitrophenyl-beta-D-galactopyranoside
-
 Escherichia coli ?
-
 ?
2.3.1.18 p-nitrophenyl-beta-D-galactopyranoside + acetyl-CoA
-
 Escherichia coli p-nitrophenyl 6-O-acetyl-beta-D-galactopyranoside + CoA
-
 ?

Subunits

EC Number Subunits Comment Organism
2.3.1.18 homotrimer
-
 Escherichia coli
2.3.1.18 trimer 3 * 28000, recombinant enzyme, SDS-PAGE Escherichia coli

Synonyms

EC Number Synonyms Comment Organism
2.3.1.18 galactoside O-acetyltransferase
-
 Escherichia coli
2.3.1.18 galactoside transacetylase
-
 Escherichia coli
2.3.1.18 LacA
-
 Escherichia coli

Temperature Optimum [°C]

EC Number Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
2.3.1.18 25
-
 assay at Escherichia coli
2.3.1.18 25
-
 activity assay Escherichia coli

Turnover Number [1/s]

EC Number Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
2.3.1.18 0.006
-
 4-nitrophenyl-beta-D-galactopyranoside 25°C, mutant Y83L Escherichia coli
2.3.1.18 0.006
-
 p-nitrophenyl-beta-D-galactopyranoside hexahistidine-tagged Y83L mutant Escherichia coli
2.3.1.18 0.0082
-
 p-nitrophenyl-beta-D-galactopyranoside H155A variant Escherichia coli
2.3.1.18 0.022
-
 4-nitrophenyl-beta-D-galactopyranoside 25°C, mutant Y83V Escherichia coli
2.3.1.18 0.022
-
 p-nitrophenyl-beta-D-galactopyranoside hexahistidine-tagged Y83V mutant Escherichia coli
2.3.1.18 0.175
-
 isopropyl-thio-beta-D-galactopyranoside hexahistidine-tagged Y83V mutant Escherichia coli
2.3.1.18 0.31
-
 isopropyl-thio-beta-D-galactopyranoside hexahistidine-tagged Y83L mutant Escherichia coli
2.3.1.18 4.9
-
 4-nitrophenyl-beta-D-galactopyranoside 25°C, mutant Y83F Escherichia coli
2.3.1.18 4.9
-
 p-nitrophenyl-beta-D-galactopyranoside hexahistidine-tagged Y83F mutant Escherichia coli
2.3.1.18 11.1
-
 4-nitrophenyl-beta-D-galactopyranoside 25°C, wild-type enzyme Escherichia coli
2.3.1.18 11.1
-
 p-nitrophenyl-beta-D-galactopyranoside hexahistidine-tagged wild type enzyme Escherichia coli
2.3.1.18 14.7
-
 p-nitrophenyl-beta-D-galactopyranoside wild type enzyme Escherichia coli
2.3.1.18 122
-
 isopropyl-thio-beta-D-galactopyranoside hexahistidine-tagged wild type enzyme Escherichia coli
2.3.1.18 133
-
 isopropyl-thio-beta-D-galactopyranoside wild type enzyme Escherichia coli
2.3.1.18 168
-
 isopropyl-thio-beta-D-galactopyranoside hexahistidine-tagged Y83F mutant Escherichia coli

Cofactor

EC Number Cofactor Comment Organism Structure
2.3.1.18 acetyl-CoA
-
 Escherichia coli