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

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 x 10(3) M (1) s (1) and K-M = 0.09 mu M. 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. (C) 2008 Elsevier Ltd. All rights reserved.