G4155

β-Galactosidase from Escherichia coli

aqueous glycerol suspension, ≥500 units/mg protein (biuret)

• Synonym(s): β-D-Galactoside galactohydrolase, Lactase
• CAS Number: 9031-11-2
• EC Number: 3.2.1.23 (BRENDA, IUBMB)
• MDL number: MFCD00155434
• UNSPSC Code: 12352204
• NACRES: NA.54

Properties

• form: aqueous glycerol suspension
• Quality Level: 200
• specific activity: ≥500 units/mg protein (biuret)
• mol wt: 465 kDa
• storage temp.: −20°C

Description

Application

β-Galactosidase is used in the enzymatic assays in the synthesis of imidazolo-pyrrolidinoses.

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

Suspension in 50% glycerol, 5 mM Tris buffer salts, 5 mM magnesium chloride, 0.5 mM DTT, 0.5 mM mercaptoethanol. pH 7.4

Other Notes

Loss of enzymatic activity can occur if this enzyme is frozen. This enzyme is provided in a 50% glycerol solution and will not freeze if stored at -20° Celsius. It is not recommended that this enzyme preparation be stored in an ultracold freezer (-60 to -100° Celsius).

Safety Information

• Storage Class Code: 10 - Combustible liquids
• WGK: WGK 2
• Flash Point(F): Not applicable
• Flash Point(C): Not applicable