Peptides labeled with FRET systems are often used in fluorescent protease assays. In this system, a protease substrate is labeled at two positions with a corresponding FRET pair. Upon proteolytic cleavage, the FRET partners are separated and the FRET effect is suppressed. Fluorescence is generated (A: in case of a quencher) or shifted to different wavelengths (B: in case of two fluorophores). This enables a positive readout with a high signal-to-noise ratio.
Excitation / Emission Maxima of the Fluorophore Components
fluorophore | excitation | emission |
Abz | 320 nm | 420 nm |
EDANS | 340 nm | 490 nm |
5-Fluo | 490 nm | 520 nm |