operator site. However, when lactose and glucose are both available in the system, the lac operon is repressed. This is because glucose actively prevents the induction of lacZYA. ara operon In the ara operon (also known as the ara or araBAD operon), arabinose acts as both an inducer and a repressor. When arabinose is present, it allosterically binds to the regulatory protein AraC, which then helps to recruit RNA polymerase for transcription. Potency Index inducer or just inducer predictably induce metabolism via a given pathway and are commonly used in prospective clinical drug-drug interaction studies. Strong, moderate, and weak inducers are drugs that decreases the AUC of sensitive index substrates of a given metabolic pathway by ≥80%, ≥50% to <80%, and ≥20% to <50%, respectively. References External links Gene expression Organic compounds