Why is it advantageous for a repressor like the lac repressor to be inactivated by binding to allolactose rather than by proteolytic cleavage? Match the words in the left column to the appropriate blanks in the sentences on the right. Proteolytic cleavage is used to inactivate repressors in an essentially process, such as in activation of a viral reproduction program. Repressor inactivation by binding a small molecule allows for changes in gene expression under conditions where concentrations of metabolites in the medium might be, and it the wasteful degradation and resynthesis of regulatory proteins.