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Literature summary for 3.2.1.23 extracted from

  • Hu, X.; Robin, S.; OConnell, S.; Walsh, G.; Wall, J.G.
    Engineering of a fungal beta-galactosidase to remove product inhibition by galactose (2010), Appl. Microbiol. Biotechnol., 87, 1773-1782.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expressed in Pichia pastoris as a His-tagged fusion protein Aspergillus niger

Protein Variants

Protein Variants Comment Organism
S259F/P261T/L262S/G263S mutant shows slightly reduced affinity for substrate (Km: 3.76 mM), 8.5fold reduction in inhibition by galactose, maximal activity lower than wild-type, pH stability lower than wild-type Aspergillus niger

Inhibitors

Inhibitors Comment Organism Structure
D-galactose
-
Aspergillus niger

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
2.21
-
2-nitrophenyl beta-D-galactopyranoside wild-type, pH 5.5, 42° Aspergillus niger
3.76
-
2-nitrophenyl beta-D-galactopyranoside mutant S259F/P261T/L262S/G263S, pH 5.5, 42° Aspergillus niger

Organism

Organism UniProt Comment Textmining
Aspergillus niger B6HYI9
-
-

Purification (Commentary)

Purification (Comment) Organism
using Ni-NTA chromatography Aspergillus niger

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2-nitrophenyl beta-D-galactopyranoside + H2O
-
Aspergillus niger 2-nitrophenol + beta-D-galactose
-
?

Synonyms

Synonyms Comment Organism
beta-galactosidase
-
Aspergillus niger

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
2.5
-
wild-type Aspergillus niger
4.5
-
mutant S259F/P261T/L262S/G263S Aspergillus niger

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.76
-
D-galactose wild-type, pH 5.5, 42° Aspergillus niger
6.46
-
D-galactose mutant S259F/P261T/L262S/G263S, pH 5.5, 42° Aspergillus niger