A FRET-based probe with a chemically deactivatable quencherElectronic supplementary information (ESI) available. See DOI: 10.1039/c2cc17542h

A new concept of a chemically deactivatable quencher is proposed for a FRET-based probe that turns-on its fluorescence by either an enzymatic cleavage or a chemical reagent (sodium dithionite). This concept allowed us to quantify the caspase-3 cleavage activity in solution and to reveal unreacted probes in cell experiments. A new concept of a chemically deactivatable quencher is proposed for a FRET-based probe that turns-on its fluorescence by either an enzymatic cleavage or a chemical reagent (sodium dithionite).