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G5635

Sigma-Aldrich

β-Galactosidase from Escherichia coli

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
Pricing and availability is not currently available.

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.[1]

Application

β-Galactosidase is conjugated to an antibody which specifically recognizes a target molecule (enzyme immunoassay or EIA).[2] β-Galactosidase is also used as a reporter enzyme to monitor the level of gene expression of a promoter.[3] 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 Code

11 - Combustible Solids

WGK

WGK 3

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Certificates of Analysis (COA)

Lot/Batch Number
0000389752
0000369267
0000352519
0000352520
0000352519

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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
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
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
Assays for bacterial mucin-desulfating sulfatases.
A M Roberton et al.
Methods in molecular biology (Clifton, N.J.), 125, 417-426 (2000-05-23)
PURIFICATION, COMPOSITION, AND MOLECULAR WEIGHT OF THE BETA-GALACTOSIDASE OF ESCHERICHIA COLI K12.
G R CRAVEN et al.
The Journal of biological chemistry, 240, 2468-2477 (1965-06-01)
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Articles

HPLC Analysis of Protein Standards (1) on BIOshell™ A400 Protein C4

For use as a marker in SDS-PAGE; Albumin from chicken egg white, For use as a marker in SDS-PAGE; L-Lactic Dehydrogenase from rabbit muscle, Type XI, lyophilized powder, 600-1,200 units/mg protein

1 Review This action will navigate to reviews.

Questions

1–2 of 2 Questions  

  1. Can this product be stores dissolved in PBS at -20 C?

    1 answer

    1. The solution stability and storage of this product in PBS have not been determined. However, according to the Product Datasheet, solutions of this enzyme should be prepared fresh. Alternatively, a prepared solution of this enzyme is available as product G4155. This solution is stored at -20°C and contains 50% glycerol, 5 mM Tris buffer salts, 5 mM magnesium chloride, 0.5 mM DTT, and 0.5 mM mercaptoethanol at pH 7.4. Please see the links below for additional information.

      G5635 Datasheet:
      https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/documents/211/865/g5635pis.pdf

      G4155 B-Galactosidase aqeuous suspension:
      https://www.sigmaaldrich.com/product/sigma/g4155

      Helpful?

  2. Should b-gal solution be prepared in 50 mM Tris HCl, 10 mM beta-mercaptoethanol and 10 mM MgCl2, as advised in PIS? Because these components were in buffer prior to lyophilization (10 mM Tris HCl, 10 mM MgCl2, and 1 mM beta-mercaptoethanol). Thanks

    1 answer

    1. For immediate use and analysis, Product G5635 can be reconstituted in 100 mM Sodium Phosphate Buffer, pH 7.3 as shown in the enzymatic assay:
      https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/documents/332/599/g5635enz.pdf

      However, oxidation may be minimized and stability may be improved by preparing solutions in 50 mM Tris HCl, pH 7.3, 5-10 mM BME, and 10 mM MgCl2.

      Helpful?

Reviews

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  1. Cincinnati, OH
    • Review 1
    • Votes 0
    3 out of 5 stars.

    Awkward sample container

    The glass vial & foil top packaging for this sample was difficult to work with. It was frustrating trying to recover all of the sample from the vial.

    For this reason alone I’m inclined to find another ordering option for this sample in the future...

    Helpful?

    1. Response from MilliporeSigma:

      Thank you for your review. We encourage customers who experience problems with our products to call or email us for additional technical support. Please visit https://www.sigmaaldrich.com/US/en/support/customer-support to submit a Product Technical Inquiry.

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