Z-Phe-Arg-AMC (70382-26-2) is a fluorogenic substrate1 for the following cathepsins (kcat/Km in M-1s-1): B (105)2, C/DPP-I (104)3, F (106)4, K/O2 (105)3, L (106)3, L2/V (105)5, O6, S (104)7, X/Z (104)8. The peptide is also cleaved by plasma kallikrein and kallikrein 89, and papain (kcat/Km=105 M-1s-1).3?Excitation: 365nm, Emission: 440nm.5