Function
α-Galactosidase (Agal) hydrolyzes the terminal α-galactosyl moiety from glycoproteins and glycolipids[1]. β-Galactosidase (Bgal) hydrolyzes β-galactosides into monosaccharides[2].
Isopropyl-β-d-thiogalactopyranoside (IPTG) induces Bgal activity. Phenylethyl-β-d-thiogalactopyranoside (PETG) is an inhibitor. Galactose, lactose, o-nitrophenyl-β-d-galactoside (ONPG) are substrates. Galactopyranosyl is reaction intermediate.
For details on α-galactosidase see Garman lab: Interconversion of lysosomal enzyme specificities.
For details on β-galactosidase see Molecular Playground/Beta-galactosidase.
See also: Beta-galactosidase (hebrew)
Relevance
Bgal assay is used in molecular biology to monitor gene expression.
Disease
The inherited deficiency of Agal is the cause of Fabry disease[3]. Bgal mutations causing enzyme deficiency can lead to ganglioidosis[4].
Structural highlights
The . The is seen in a [5]. Water molecules shown as red spheres.
For 3hg2 .
3D Structures of Galactosidase
Galactosidase 3D structures