Fmoc-ACA-OH is a useful tool for the SPPS of AMC fluorogenic protease substrates. Fmoc-ACA-OH [1] must be first loaded onto a Wang-type resin. Any unreacted linker hydroxyls must be capped using acetic anhydride. Following Fmoc removal, the first amino acid should be coupled withy HATU/collidine [2]. Insertion of ACA into the middle of a peptide provides fluorogenic substrates for endopeptidases [3]. Treatment of the ACC peptide obtained after TFA cleavage with aqueous base causes facile decarboxylation and formation of the AMC peptide.