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Literature summary for 3.2.1.23 extracted from

  • Juers, D.H.; Rob, B.; Dugdale, M.L.; Rahimzadeh, N.; Giang, C.; Lee, M.; Matthews, B.W.; Huber, R.E.
    Direct and indirect roles of His-418 in metal binding and in the activity of beta-galactosidase (E. coli) (2009), Protein Sci., 18, 1281-1292.
    View publication on PubMedView publication on EuropePMC

Crystallization (Commentary)

Crystallization (Comment) Organism
mutant enzymes H418E and H418N Escherichia coli

Protein Variants

Protein Variants Comment Organism
H418E the mutant shows low catalytic activity Escherichia coli
H418F the mutant shows low catalytic activity, the variant has reduced stability, binds Mg2+ weakly and cannot be crystallized Escherichia coli
H418N the mutant shows low catalytic activity Escherichia coli

Inhibitors

Inhibitors Comment Organism Structure
2-amino-2-deoxy-D-galactopyranose
-
Escherichia coli
2-nitrophenyl 1-thio-beta-D-galactopyranoside
-
Escherichia coli
2-phenylethyl 1-thio-beta-D-galactopyranoside
-
Escherichia coli
D-galactonolactone
-
Escherichia coli
D-galactose
-
Escherichia coli
isopropyl-thio-beta-D-galactopyranoside
-
Escherichia coli
L-arabinose
-
Escherichia coli
L-ribose
-
Escherichia coli
lactose
-
Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.04
-
4-nitrophenyl beta-D-galactopyranoside mutant enzyme H418N, in 30 mM TES buffer, 0.01 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
0.04
-
2-nitrophenyl beta-D-galactopyranoside wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, pH 7.0 at 25°C Escherichia coli
0.06
-
2-nitrophenyl beta-D-galactopyranoside mutant enzyme H418N, in 30 mM TES buffer, 0.01 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
0.12
-
4-nitrophenyl beta-D-galactopyranoside wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, pH 7.0 at 25°C Escherichia coli
13.2
-
4-nitrophenyl beta-D-galactopyranoside mutant enzyme H418E, in 30 mM TES buffer, 0.01 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
20.8
-
4-nitrophenyl beta-D-galactopyranoside mutant enzyme H418F, in 30 mM TES buffer, 10 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
30.6
-
2-nitrophenyl beta-D-galactopyranoside mutant enzyme H418F, in 30 mM TES buffer, 10 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
104
-
2-nitrophenyl beta-D-galactopyranoside mutant enzyme H418E, in 30 mM TES buffer, 0.01 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ the active site of beta-galactosidase contains a Mg2+ ion ligated by Glu-416, His-418 and Glu-461 plus three water molecules Escherichia coli
Na+ the active site of beta-galactosidase contains a Na+ ion Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
lactose + H2O Escherichia coli
-
D-galactose + D-glucose
-
?

Organism

Organism UniProt Comment Textmining
Escherichia coli P00722
-
-

Purification (Commentary)

Purification (Comment) Organism
Superose 6 gel filtration and Superose 12 gel filtration Escherichia coli

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2-nitrophenyl beta-D-galactopyranoside + H2O
-
Escherichia coli 2-nitrophenol + beta-D-galactose
-
?
4-nitrophenyl beta-D-galactopyranoside + H2O
-
Escherichia coli 4-nitrophenol + beta-D-galactose
-
?
lactose + H2O
-
Escherichia coli D-galactose + D-glucose
-
?

Subunits

Subunits Comment Organism
homotetramer x-ray crystallography Escherichia coli

Synonyms

Synonyms Comment Organism
beta-gal
-
Escherichia coli
BGA
-
Escherichia coli

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
4.9
-
2-nitrophenyl beta-D-galactopyranoside mutant enzyme H418N, in 30 mM TES buffer, 0.01 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
5.4
-
2-nitrophenyl beta-D-galactopyranoside mutant enzyme H418E, in 30 mM TES buffer, 0.01 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
5.4
-
4-nitrophenyl beta-D-galactopyranoside mutant enzyme H418E, in 30 mM TES buffer, 0.01 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
5.5
-
4-nitrophenyl beta-D-galactopyranoside mutant enzyme H418N, in 30 mM TES buffer, 0.01 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
10.3
-
4-nitrophenyl beta-D-galactopyranoside mutant enzyme H418F, in 30 mM TES buffer, 10 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
10.4
-
2-nitrophenyl beta-D-galactopyranoside mutant enzyme H418F, in 30 mM TES buffer, 10 mM Mg2+, 150 mM Na+, pH 7.0 at 25°C Escherichia coli
90
-
2-nitrophenyl beta-D-galactopyranoside wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, pH 7.0 at 25°C Escherichia coli
620
-
4-nitrophenyl beta-D-galactopyranoside wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, pH 7.0 at 25°C Escherichia coli

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.002
-
2-phenylethyl 1-thio-beta-D-galactopyranoside wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
0.025
-
2-nitrophenyl 1-thio-beta-D-galactopyranoside wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
0.08
-
2-phenylethyl 1-thio-beta-D-galactopyranoside mutant enzyme H418N, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
0.08
-
isopropyl-thio-beta-D-galactopyranoside wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
0.28
-
L-ribose wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
0.4
-
D-galactonolactone mutant enzyme H418E, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
0.4
-
D-galactonolactone mutant enzyme H418N, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
0.64
-
D-galactonolactone wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
0.68
-
L-ribose mutant enzyme H418N, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
0.9
-
lactose wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
1
-
2-amino-2-deoxy-D-galactopyranose wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
1.3
-
2-amino-2-deoxy-D-galactopyranose mutant enzyme H418E, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
1.4
-
L-ribose mutant enzyme H418E, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
1.4
-
2-amino-2-deoxy-D-galactopyranose mutant enzyme H418N, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
2 5 L-arabinose mutant enzyme H418N, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
3.3
-
D-galactose mutant enzyme H418N, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
3.4
-
D-galactose mutant enzyme H418E, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
4.2
-
2-nitrophenyl 1-thio-beta-D-galactopyranoside mutant enzyme H418N, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
5
-
isopropyl-thio-beta-D-galactopyranoside mutant enzyme H418N, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
5.1
-
lactose mutant enzyme H418N, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
8.4
-
2-nitrophenyl 1-thio-beta-D-galactopyranoside mutant enzyme H418E, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
10
-
2-phenylethyl 1-thio-beta-D-galactopyranoside mutant enzyme H418E, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
13
-
lactose mutant enzyme H418E, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
21
-
D-galactose wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
85
-
isopropyl-thio-beta-D-galactopyranoside mutant enzyme H418E, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
130
-
L-arabinose mutant enzyme H418E, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli
220
-
L-arabinose wild type enzyme, in 30 mM TES buffer, 145 mM NaCl, 0.01 mM Mg2+, pH 7.0 at 25°C Escherichia coli