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G5635

Sigma-Aldrich

β-Galactosidase from Escherichia coli

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

Synonym(s):

β-D-Galactoside galactohydrolase, Lactase

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About This Item

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

Storage Class

11 - Combustible Solids

wgk_germany

WGK 3

flash_point_f

Not applicable

flash_point_c

Not applicable

ppe

Eyeshields, Gloves, type N95 (US)

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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
Assays for bacterial mucin-desulfating sulfatases.
A M Roberton et al.
Methods in molecular biology (Clifton, N.J.), 125, 417-426 (2000-05-23)
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
Toshiya Suzuki et al.
Plant physiology, 173(1), 183-205 (2016-11-12)
Pollen exine is essential for protection from the environment of the male gametes of seed-producing plants, but its assembly and composition remain poorly understood. We previously characterized Arabidopsis (Arabidopsis thaliana) mutants with abnormal pollen exine structure and morphology that we
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