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Literature summary for 3.2.1.23 extracted from

  • Holmes, M.L.; Scopes, R.K.; Moritz, R.L.; Simpson, R.J.; Englert, C.; Pfeifer, F.; Dyall-Smith, M.L.
    Purification and analysis of an extremely halophilic beta-galactosidase from Haloferax alicantei (1997), Biochim. Biophys. Acta, 1337, 276-286.
    View publication on PubMed
Search for more literature for 3.2.1.23

Protein Variants

Protein Variants Comment Organism
additional information an overproducing mutant is isolated by UV mutagenesis and screening on agar plates containing X-Gal substrate. Cytoplasmic extracts of the mutant contain 25fold higher enzyme levels than the parent Haloferax lucentense

General Stability

General Stability Organism
activity is irreversibly lost within min in low salt buffers, below 0.5 M Haloferax lucentense

Inhibitors

Inhibitors Comment Organism Structure
Cu2+ 1 mM Haloferax lucentense
EDTA 5-20 mM Haloferax lucentense
glycerol interferes with enzyme activity Haloferax lucentense
additional information loss in activity if dithiothreitol or 2-mercaptoethanol is omitted from buffers although this effect appears to be reversible, indicating the presence of an active thiol in the enzyme Haloferax lucentense
Zn2+ 1 mM Haloferax lucentense

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.87
-
 2-nitrophenyl beta-D-galactoside pH 7.2, 22°C, the enzyme also shows beta-fucosidase activity Haloferax lucentense

Metals/Ions

Metals/Ions Comment Organism Structure
KCl the activity of the enzyme in 2.5 M and 4 M KCl relative to 4 M NaCl is 34% and 40%, respectively Haloferax lucentense
NaCl optimally active at 4 M NaCl Haloferax lucentense

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
78000
-
 2 * 78000, SDS-PAGE Haloferax lucentense
180000
-
 gel filtration Haloferax lucentense

Organic Solvent Stability

Organic Solvent Comment Organism
Glycerol 20% v/v, stabilizes the enzyme in buffers with no salt Haloferax lucentense
sorbitol 30% v/v, stabilizes the enzyme in buffers with no salt. The enzyme is stable in 30% sorbitol for at least four months at -20°C, but at room temperature approximately 20% of specific activity is lost after 48 h Haloferax lucentense

Organism

Organism UniProt Comment Textmining
Haloferax lucentense P94804
-
-
Haloferax lucentense DSM 14919 P94804
-
-

Purification (Commentary)

Purification (Comment) Organism
-
 Haloferax lucentense

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
42
-
 substrate: 2-nitrophenyl-beta D-galactoside, pH 7.2, 22°C, the enzyme also shows beta-fucosidase activity Haloferax lucentense

Storage Stability

Storage Stability Organism
-20°C, 50% loss of activity when stored overnight Haloferax lucentense
4°C, 18% loss of activity when stored overnight Haloferax lucentense

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2-nitrophenyl beta-D-galactoside + H2O the enzyme also shows beta-fucosidase activity Haloferax lucentense 2-nitrophenol + beta-D-galactose
-
 ?
4-nitrophenyl beta-D-fucopyranoside + H2O 43% relative to 2-nitrophenyl-beta-D-galactoside hydrolysis Haloferax lucentense 4-nitrophenol + beta-D-fucose
-
 ?
lactulose + H2O the enzyme also shows beta-fucosidase activity Haloferax lucentense D-galactose + D-fructose
-
 ?
additional information no beta-glucosidase, beta-arabinosidase or beta-xylosidase activity can be detected Haloferax lucentense ?
-
 ?
additional information no beta-glucosidase, beta-arabinosidase or beta-xylosidase activity can be detected Haloferax lucentense DSM 14919 ?
-
 ?

Subunits

Subunits Comment Organism
dimer 2 * 78000, SDS-PAGE Haloferax lucentense

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
22
-
 assay at room temperature Haloferax lucentense

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
22
-
 stable in 3 M NaCl for several days at room temperature Haloferax lucentense

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.2
-
 assay at Haloferax lucentense