β-galactosidase, also called beta-gal or β-gal, 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/-1-346-Galactosidase-From-Streptococcus-Pneumoniae-And-Xanthomonas-Sp-Recombinant_1563.html