Final answer:
The regulatory protein removed from the promoter by allolactose in E. coli is a repressor protein, specifically involved in the control of the Lac Operon, which is an inducible operon.
Step-by-step explanation:
The regulatory protein you are referring to is classified as a repressor protein. When allolactose, which is formed from lactose inside an E. coli cell, binds to the repressor protein, it induces a conformational change that prevents the repressor from binding to the operator region of the Lac Operon. This removal of the repressor allows RNA polymerase to access the promoter and initiate transcription of the genes necessary for lactose metabolism. The Lac Operon is a classic example of an inducible operon activated in the presence of an inducer molecule, in this case, allolactose.