G5635

β-Galactosidase from Escherichia coli

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

• 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

Properties

• 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

Description

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

Safety Information

• 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