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G5635

Sigma-Aldrich

β-Galactosidase from Escherichia coli

Grade VIII, lyophilized powder, ≥500 units/mg protein

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Synonym(s):
β-D-Galactoside galactohydrolase, Lactase
CAS Number:
9031-11-2
Enzyme Commission number:
3.2.1.23 (BRENDA, IUBMB)
EC Number:
232-864-1
MDL number:
MFCD00130623
UNSPSC Code:
12352204
NACRES:
NA.54

type

Grade VIII

Quality Level

300

form

lyophilized powder

specific activity

≥500 units/mg protein

mol wt

465 kDa

does not contain

BSA as extender

composition

Protein, ≥60% biuret

storage temp.

−20°C

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General description

β-Galactosidase is a tetramer consisting of four equal subunits of 135,000 each. It is a sulfhydryl containing enzyme, with 19 cysteine residues per subunit.

Application

β-Galactosidase is conjugated to an antibody which specifically recognizes a target molecule (enzyme immunoassay or EIA). β-Galactosidase is also used as a reporter enzyme to monitor the level of gene expression of a promoter. It may be used as a positive control protein with anti-β-galactosidase antibodies.

Biochem/physiol Actions

β-galactosidase cleaves lactose into its monosaccharide components, glucose and galactose. It also catalyses the transglycosylation of glucose into allolactose, the inducer of β-galactosidase, in a feedback loop.

Physical properties

Tetramer molecular weight 465 kDa (subunits 116.3 kDa each)

Unit Definition

One unit will hydrolyze 1.0 μmole of o-nitrophenyl β-D-galactoside to o-nitrophenol and D-galactose per min at pH 7.3 at 37 °C.

Physical form

Contains Tris buffer salts and magnesium chloride

inhibitor

Product No.
Description
Pricing

substrate

Product No.
Description
Pricing

WGK

WGK 3

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Regulatory Information

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Alan Merk et al.
IUCrJ, 7(Pt 4), 639-643 (2020-07-23)
We report the determination of the structure of Escherichia coli β-galactosidase at a resolution of ∼1.8 Å using data collected on a 200 kV CRYO ARM microscope equipped with a K3 direct electron detector. The data were collected in a single 24 h
K Kato et al.
Journal of immunology (Baltimore, Md. : 1950), 116(6), 1554-1560 (1976-06-01)
1. A method for the conjugation of the Fab' fragment of rabbit IgG with beta-D-galactosidase from Escherichia coli is described. The method consists of two main steps: treatment of the Fab' fragments containing sulfhydryl groups with excess N,N'-o-phenylenedimaleimide, to introduce
Raimond B G Ravelli et al.
Nature communications, 11(1), 2563-2563 (2020-05-24)
The increasing demand for cryo-electron microscopy (cryo-EM) reveals drawbacks in current sample preparation protocols, such as sample waste and lack of reproducibility. Here, we present several technical developments that provide efficient sample preparation for cryo-EM studies. Pin printing substantially reduces
Assays for bacterial mucin-desulfating sulfatases.
A M Roberton et al.
Methods in molecular biology (Clifton, N.J.), 125, 417-426 (2000-05-23)
D C Young et al.
Analytical biochemistry, 215(1), 24-30 (1993-11-15)
Bacterial beta-galactosidase is one of several reporter enzymes used in studying the transcriptional activity of eukaryotic promoters. Although it is one of the easiest and least expensive enzymes to assay, its use has been limited because of its low sensitivity
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