Keap1-Nrf2 is a major regulator of cellular protective responses to oxidative and electrophilic stress. Ech-associated protein 1, similar to Kelch, is a protein encoded by the Keap1 gene in humans. Keap1 has been shown to interact with Nrf2, which is a major regulator of antioxidant responses and is important for improving oxidative stress. Under static conditions, Nrf2 is anchored in the cytoplasm by binding to Keap1, which in turn promotes ubiquitous proteinization and subsequent proteolysis of Ndf2. This isolation and further degradation of Nrf2 in the cytoplasm is the mechanism of inhibition of Nrf2 by Keap1. Because Nrf2 activation leads to coordinated antioxidant and anti-inflammatory responses, and Keap1 inhibits Nrf2 activation, Keap1 has become a very attractive drug target.