lacY gene product is
lacY gene product is lactose permease LacY, 417-residue member of major facilitator superfamily transporter folded into twelve transmembrane alpha helices forming central hydrophilic cavity accessible alternately outward and inward during cycle. It operates as galactoside-proton symporter driven entirely by proton motive force, accumulating lactose against concentration gradient for metabolic use. Protein functionality is distinct from soluble beta-galactosidase encoded by lacZ and transacetylase LacA. By concentrating intracellular beta-galactosides, LacY enables efficient generation of allol
Ref: ScienceDirect Lactose Permease overview – LacY transmembrane symporter concentrates β-galactosides for hydrolysis and induction.
