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Literature summary extracted from

  • Lo, S.; Dugdale, M.L.; Jeerh, N.; Ku, T.; Roth, N.J.; Huber, R.E.
    Studies of Glu-416 variants of beta-galactosidase (E. coli) show that the active site Mg2+ is not important for structure and indicate that the main role of Mg2+ is to mediate optimization of active site chemistry (2010), Protein J., 29, 26-31.
    View publication on PubMed

Crystallization (Commentary)

EC Number Crystallization (Comment) Organism
3.2.1.23 mutant enzymes E416Q and E416V Escherichia coli

Protein Variants

EC Number Protein Variants Comment Organism
3.2.1.23 E416Q the mutant enzyme does not have a Mg2+ bound at the active site even at high Mg2+ concentrations (200 mM), low catalytic activity and the pH profile is very different from that of the native enzyme Escherichia coli
3.2.1.23 E416V the mutant enzyme does not have a Mg2+ bound at the active site even at high Mg2+ concentrations (200 mM), low catalytic activity and the pH profile is very different from that of the native enzyme Escherichia coli

Inhibitors

EC Number Inhibitors Comment Organism Structure
3.2.1.23 D-galactonolactone
-
 Escherichia coli
3.2.1.23 D-galactose
-
 Escherichia coli
3.2.1.23 lactose
-
 Escherichia coli

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
3.2.1.23 0.12
-
 2-nitrophenyl-beta-D-galactopyranoside native enzyme Escherichia coli
3.2.1.23 9.5
-
 2-nitrophenyl-beta-D-galactopyranoside mutant enzyme E416V Escherichia coli
3.2.1.23 18
-
 2-nitrophenyl-beta-D-galactopyranoside mutant enzyme E416Q Escherichia coli

Metals/Ions

EC Number Metals/Ions Comment Organism Structure
3.2.1.23 Mg2+ beta-galactosidase requires Mg2+ for full catalytic activity, one Mg2+ is at each active site but 3-4 others bind to other parts of each subunit Escherichia coli

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
3.2.1.23 lactose + H2O Escherichia coli
-
 D-galactose + D-glucose
-
 ?
3.2.1.23 lactose + H2O Escherichia coli LMG194
-
 D-galactose + D-glucose
-
 ?

Organism

EC Number Organism UniProt Comment Textmining
3.2.1.23 Escherichia coli P00722
-
-
3.2.1.23 Escherichia coli LMG194 P00722
-
-

Purification (Commentary)

EC Number Purification (Comment) Organism
3.2.1.23 ProBond Ni column chromatography Escherichia coli

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
3.2.1.23 2-nitrophenyl beta-D-galactopyranoside + H2O
-
 Escherichia coli 2-nitrophenol + beta-D-galactose
-
 ?
3.2.1.23 2-nitrophenyl beta-D-galactopyranoside + H2O
-
 Escherichia coli LMG194 2-nitrophenol + beta-D-galactose
-
 ?
3.2.1.23 lactose + H2O
-
 Escherichia coli D-galactose + D-glucose
-
 ?
3.2.1.23 lactose + H2O
-
 Escherichia coli LMG194 D-galactose + D-glucose
-
 ?

Synonyms

EC Number Synonyms Comment Organism
3.2.1.23 beta-gal
-
 Escherichia coli
3.2.1.23 BGA
-
 Escherichia coli

Turnover Number [1/s]

EC Number Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
3.2.1.23 54
-
 2-nitrophenyl-beta-D-galactopyranoside mutant enzyme E416Q Escherichia coli
3.2.1.23 81
-
 2-nitrophenyl-beta-D-galactopyranoside mutant enzyme E416V Escherichia coli
3.2.1.23 620
-
 2-nitrophenyl-beta-D-galactopyranoside native enzyme Escherichia coli

Ki Value [mM]

EC Number Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
3.2.1.23 0.6
-
 D-galactonolactone native enzyme Escherichia coli
3.2.1.23 1
-
 lactose native enzyme Escherichia coli
3.2.1.23 4.9
-
 D-galactonolactone mutant enzyme E416V Escherichia coli
3.2.1.23 24
-
 D-galactose native enzyme Escherichia coli
3.2.1.23 24
-
 D-galactonolactone mutant enzyme E416Q Escherichia coli
3.2.1.23 107
-
 lactose mutant enzyme E416V Escherichia coli
3.2.1.23 154
-
 lactose mutant enzyme E416Q Escherichia coli
3.2.1.23 211
-
 D-galactose mutant enzyme E416V Escherichia coli
3.2.1.23 220
-
 D-galactose mutant enzyme E416Q Escherichia coli