A highly sensitive fluorogenic probe for cytochrome P450 activity in live cells

Abstract A derivative of rhodamine 110 has been designed and assessed as a probe for cytochrome P450 activity. This probe is the first to utilize a ‘trimethyl lock’ that is triggered by cleavage of an ether bond. In vitro, fluorescence was manifested by the CYP1A1 isozyme with k cat / K M  = 8.8 × 10 3  M −1  s −1 and K M  = 0.09 μM. In cellulo, the probe revealed the induction of cytochrome P450 activity by the carcinogen 2,3,7,8-tetrachlorodibenzo- p -dioxin, and its repression by the chemoprotectant resveratrol.