Lac operon is the gene regulatory system used by E.coli to digest the disaccharide lactose to glucose and galactose.
In lac operon of E.coli, there are three structural genes (z, y, and a) which are required for metabolism of lactose, these are regulated by a common promoter and regulatory gene (i gene).
Regulatory gene i – Codes for the repressor protein.
z gene – Responsible for coding for beta-galactosidase which further catalyzes the hydrolysis of lactose into glucose and galactose.
y gene – This gene codes for permease that is responsible for regulating the lactose permeability in the cell.
a gene – This gene codes for transacetylase which helps the enzyme beta-galactosidase.
