Beta-galactosidase is a hydrolase enzyme that catalyzes the hydrolysis of Beta-galactosides into monosaccharides. Substrates of different Beta-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins. Beta-galactosidase is produced In E. coli by activation of the lac operon as the lacZ gene.