[Fluorescent substrates of proteolytic enzymes with internal quenching of fluorescence]

The design and application of a successfully developed type of fluorogenic substrates for proteolytic enzymes are discussed. Proteolytic enzymes play a key role not only in the regulation of cellular protein turnover but also in the control of many other physiological functions. Substrates consisting of the appropriate peptides with chromophore or fluorophore at the C-termini are often employed to detect protease activity. Proteases exhibit the primary specificity to the particular amino acid residue and hydrolyze the following peptide bond. However, it is impossible to investigate the specific recognition of the other side of a scissible bond. Intramolecularly quenched fluorescent substrates are very useful instruments for research and medical purpose due to their high sensitivity and selectivity to proteases.