L-Phenylalanine 7-Amido-4-methylcoumarin, Trifluoroacetate Salt is a fluorogenic substrate for phenylalanine peptidase yielding a blue fluorescent solution from cleavage. L-Phenylalanine 7-Amido-4-methylcoumarin, Trifluoroacetate Salt can be used as reactant/reagent for activation of lymphocyte progranzyme by dipeptidyl peptidase I.