The Sortase A Assay Kit is a fluorogenic assay kit designed to measure Sortase A proteolytic activity for screening and profiling applications.

Figure 1: Illustration of the assay principle.

The fluorescence emitted by donor DNP is quenched due to the proximity of the Abz acceptor in the intact peptide. The protease cleaves the peptide between T (threonine) and G (glycine) and forms an intermediate complex between the cysteine residue within the active site and the C-terminus of the peptide substrate. The cleaved substrate is then covalently bounded to the triglycine nucleophile. The glycine-DNP fragment is released, freeing the emission of fluorescence by DNP.