β-galactosidase is a hydrolase enzyme that catalyzes the hydrolysis of β-galactosides into monosaccharides. Substrates of different β-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins.http://www.creative-enzymes.com/product/Native-Aspergillus-Oryzae-Galactosidase_816.html