allolactose

Allolactose is a disaccharide used as an inducer of the lac operon in Escherichia coli and many other enteric bacteria.

β-Galactosidase, a glycoside hydrolase, breaks down β-glycosidic bonds in galactose and its derivatives. In E. coli, it is encoded by the lacZ gene, playing a crucial role in the lac operon induction system. This enzyme not only converts lactose into glucose and galactose for glycolysis but also facilitates the transgalactosylation of lactose into allolactose, which subsequently breaks down into monosaccharides [1].