Application | Comment | Organism |
---|---|---|
food industry | the enzyme is used for hydrolysis of lactose extracted from whey or milk | Lactobacillus delbrueckii |
Cloned (Comment) | Organism |
---|---|
expressed in Escherichia coli MRS32 cells | Lactobacillus delbrueckii |
Protein Variants | Comment | Organism |
---|---|---|
E491A | the mutant shows wild type optimal temperature, but displays an optimal pH at 6.5-7.0 | Lactobacillus delbrueckii |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
Cu2+ | 1 mM Cu2+ inhibits the activity more than 13fold | Lactobacillus delbrueckii | |
EDTA | 35% residual activity at 10 mM | Lactobacillus delbrueckii | |
additional information | not significantly inhibited by Fe2+, Ca2+, Mg2+, Zn2+, Ba2+, and Ni2+ | Lactobacillus delbrueckii |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.16 | - |
2-nitrophenyl-beta-D-galactopyranoside | wild type enzyme, in 100 mM sodium acetate buffer pH 5.5, at 45°C | Lactobacillus delbrueckii | |
0.17 | - |
2-nitrophenyl-beta-D-galactopyranoside | mutant enzyme E491A, in HEPES buffer pH 6.5, at 45°C | Lactobacillus delbrueckii | |
0.94 | - |
lactose | mutant enzyme E491A, in HEPES buffer pH 6.5, at 45°C | Lactobacillus delbrueckii | |
0.98 | - |
lactose | wild type enzyme, in 100 mM sodium acetate buffer pH 5.5, at 45°C | Lactobacillus delbrueckii |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Co2+ | the enzyme requires 1 mM Co2+ for optimal activity and thermostability | Lactobacillus delbrueckii | |
Mg2+ | the enzyme requires 1 mM Mn2+ for optimal activity and thermostability | Lactobacillus delbrueckii |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
110000 | - |
4 * 110000, SDS-PAGE | Lactobacillus delbrueckii |
400000 | - |
gel filtration | Lactobacillus delbrueckii |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
lactose + H2O | Lactobacillus delbrueckii | - |
D-galactose + D-glucose | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Lactobacillus delbrueckii | Q1G9Z4 | strain ATCC 11842, subspecies Lactobacillus delbrueckii bulgaricus | - |
Purification (Comment) | Organism |
---|---|
ammonium sulfate precipitation and fast-performance liquid chromatography using an anion-exchange column equilibrated with 100 mM sodium acetate buffer (pH 5.5) | Lactobacillus delbrueckii |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
2-nitrophenyl beta-D-galactopyranoside + H2O | - |
Lactobacillus delbrueckii | 2-nitrophenol + beta-D-galactose | - |
? | |
lactose + H2O | - |
Lactobacillus delbrueckii | D-galactose + D-glucose | - |
? |
Subunits | Comment | Organism |
---|---|---|
homotetramer | 4 * 110000, SDS-PAGE | Lactobacillus delbrueckii |
Synonyms | Comment | Organism |
---|---|---|
beta-gal | - |
Lactobacillus delbrueckii |
BGA | - |
Lactobacillus delbrueckii |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
35 | 50 | - |
Lactobacillus delbrueckii |
Temperature Stability Minimum [°C] | Temperature Stability Maximum [°C] | Comment | Organism |
---|---|---|---|
40 | 65 | the wild-type beta-galactosidase is fully stable at 40°C and 45°C for 16 h, respectively. At temperatures of 50, 55, 60 and 65°C wild type enzyme half-lives are 6, 3, 1.5 and 0.4 h respectively. Above 65°C occurs rapid inactivation with or without divalent ions | Lactobacillus delbrueckii |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
45.7 | - |
lactose | wild type enzyme, in 100 mM sodium acetate buffer pH 5.5, at 45°C | Lactobacillus delbrueckii | |
46.3 | - |
lactose | mutant enzyme E491A, in HEPES buffer pH 6.5, at 45°C | Lactobacillus delbrueckii | |
47.2 | - |
2-nitrophenyl-beta-D-galactopyranoside | wild type enzyme, in 100 mM sodium acetate buffer pH 5.5, at 45°C | Lactobacillus delbrueckii | |
49.2 | - |
2-nitrophenyl-beta-D-galactopyranoside | mutant enzyme E491A, in HEPES buffer pH 6.5, at 45°C | Lactobacillus delbrueckii |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
5 | 5.5 | - |
Lactobacillus delbrueckii |
pH Stability | pH Stability Maximum | Comment | Organism |
---|---|---|---|
5.5 | - |
the wild type protein retains about 90% of its activity after 32 h at pH 5.5. At pH 5.0 and 6.0 the enzyme conserves more than 50% of its initial activity after 32 h of incubation, at pH 4.5, 6.5, 7.0 and 7.5 the enzyme half-lives are 24, 28, 20 and 18 h respectively | Lactobacillus delbrueckii |
kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
46.6 | - |
lactose | wild type enzyme, in 100 mM sodium acetate buffer pH 5.5, at 45°C | Lactobacillus delbrueckii | |
47 | - |
lactose | mutant enzyme E491A, in HEPES buffer pH 6.5, at 45°C | Lactobacillus delbrueckii | |
289.4 | - |
2-nitrophenyl-beta-D-galactopyranoside | mutant enzyme E491A, in HEPES buffer pH 6.5, at 45°C | Lactobacillus delbrueckii | |
295 | - |
2-nitrophenyl-beta-D-galactopyranoside | wild type enzyme, in 100 mM sodium acetate buffer pH 5.5, at 45°C | Lactobacillus delbrueckii |