Allolactose is a molecule made of galactose and glucose joined by alpha - 1,6 glycosidic bond. It is the side product of the conversion of lactose to galactose and glucose by beta- galactosidase. Allolactose is an inducer of lac operon in prokaryotes. It binds to the lac repressor causing a comformational change which reduces the reprossor's affinity for the operator DNA. As results RNA polymerase can initiate transcription of the lac genes.
- ↑ Berg JM, Tymoczko JL, Gatto GJ, Stryer L. Biochemistry. 8th ed. New York: W.H. Freeman &amp; Commpany, a Macmillan Education Print. 2015