LAC operon

Lac I function

encodes for an active repressor

Lac O function

codes for binding site for repressor

Lac P function

codes for RNA polymerase binding site

Lac Z function

codes for beta-galactase

Lac Y function

codes for permease

Lac A function

codes for transacetylase

Lac I^- mutation

no repressor, causes lac protein production all the time, recessive

Lac I⁺ mutation

restores normal functioning for repressor even if it was located on a different chromosome

Lac I^s mutation

superrepressor that cannot be inactivated, transdominant

Lac Z mutation

no beta-galactase produced, recessive

Lac Y mutation

no permease produced, recessive

Lac A mutation

no transacetylase, recessive

beta-galactase function

breaks lactose into glucose and galactose, converts lactose into allolactose, and breaks allolactose into glucose and galactose

permease function

actively transports lactose into the cell

transacetylase function

important component in producing cAMP enhancer

Lac O^c mutation

repressor protein no longer binds, dominant, cis acting

Lac P^- mutations

interfere with the binding of RNA polymerase to the promoter, cis acting