AI-1 (75483-04-4) is a novel antioxidant response element (ARE) activator which activates Nrf2 by covalently modifying Keap1 (Kelch-like ECH-associated protein 1) a negative regulator of Nrf2. Modification of Cys151 of Keap1 by AI-1 disrupts the ability of Keap1 to serve as an adaptor for Cul3-Keap1 ubiquitin ligase complex, thereby stabilizing and inducing transcriptional activation of Nrf2. AI-1 is a useful pharmacological tool for probing the involvement of Nrf2 in cellular physiology.1?Cell permeable.