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.
The BIOSYNTAN portfolio includes various FRET pairs, which can be placed at the N- and C-terminal region of the peptide substrate. A small selection is listed below. Please inquire for any different types of FRET substrates.