In Bacoperon what happens when all the lactose has been metabolised?

Question

I understand that lactose binds to the inhibitor so that betagalactosidase can be formed, and thus lactose can be metabolised, but when the lactose concentration falls (when it's all been metabolised) does the lactose molecule ATTACHED to the inhibitor molecule get digested too? or does it just fall off?

Answer 1

Lactose binds to the repressor protein in an allosteric way. This is a not permanent bond. Which means that in the absence of lactose equlibrium will favor a repressor protein in an activated state. In other words, equilibrium will favor the release off lactose from the repressor allowing the repressor to act on the operator region of DNA.