β-Galactosidase

Chemical properties

White to tan powder

The Uses of β-Galactosidase

β-Galactosidase from bovine testes was used for coupling to Sepharose.

The Uses of β-Galactosidase

β-Galactosidase is conjugated to an antibody which specifically recognizes a target molecule (enzyme immunoassay or EIA). 1 β-Galactosidase is also used as a reporter enzyme to monitor the level of gene expression of a promoter. 2 It may be used as a positive control protein with anti-β-galactosidase antibodies.

The Uses of β-Galactosidase

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

The Uses of β-Galactosidase

β-Galactosidase may be used for derivatization, such as an enzyme label for IgG, without prior dialysis or gel filtration.

The Uses of β-Galactosidase

β-Galactosidase was used for reversed-phase (RP) adsorption. 1 It was also used in the hydrolysis of whey lactose.

The Uses of β-Galactosidase

β-galactosidase was used in the production of a stabilized, single reagent for alcohol analysis.

Definition

ChEBI: Beta-D-galactose is a D-galactopyranose having beta-configuration at the anomeric centre. It has a role as an epitope and a mouse metabolite. It is an enantiomer of a beta-L-galactose.

brand name

Replagal (Transkaryotic Therapies).

Biotechnological Production

b-D-Galactosidase (b-D-galactoside galactohydrolase, EC 3.2.1.23) hydrolyses the glycosidic bond of the disaccharide lactose into its monomers glucose and galactose. Therefore, b-D-galactosidase is also known as lactase. b-D-Galactosidases can be found throughout nature. Commercial enzymes are mainly of fungal origin of the genera Kluyveromyces (yeast) and Aspergillus (filamentous ascomycete). Although several b-D-galactosidases are available on the market, new efforts are still conducted to improve the enzymatic properties by site-directed mutagenesis or to find new b-D-galactosidase genes by screening metagenome databases.
From a technological point of view, the milk sugar lactose is hydrolyzed because of the resulting increase of sweetness and the reduced susceptibility to crystallization during spray drying of milk and whey. Nevertheless, the most apparent application is the production of ‘‘lactose-free’’ milk products, which enables the consumption of dairy products by lactose-intolerant people.
For industrial processes, b-D-galactosidases can be applied by immobilization of the enzyme on carriers, such as cellulose, alginate, or other polymers, for hydrolysis of milk or whey products. Conversion rates of lactose in batch and continuous operation mode by immobilized b-D-galactosidase might reach 95 %. To reach even lower lactose concentrations of less than 0.01 %, a combination of b-D-galactosidase activity and ultrafiltration as well as nanofiltration methods can be used. Besides the degradation of substances that lead to food intolerances, the elimination of food allergens by means of a specific degradation of allergenic epitopes is another promising application of enzymes.

General Description

The GLB1 (β-Galactosidase) gene is mapped to human chromosome 3p22.3. The encoded protein belongs to glycosyl hydrolase 35 family and is localized to lysosomes.

Biochem/physiol Actions

Releases β(1→3)- and β(1→6)-linked galactose from the non-reducing end of complex oligosaccharides.

Purification Methods

It is purified 600-fold by (NH4)2SO4 precipitation, acetone fractionation and affinity chromatography on agarose substituted with terminal thio-.-galactopyranosyl residues. [Distlern & Jourdian J Biol Chem 248 6772 1973.]