Photometric or fluorometric assay of cathepsin B, L and H and papain using substrates with an aminotrifluoromethylcoumarin leaving group.

N-trifluoromethylcoumarinylamide derivatives of benzyloxycarbonyl-Arg-Arg, benzyloxycarbonyl-Phe-Arg and Arg are convenient chromogenic and fluorogenic substrates of cathepsin B, L and H, respectively. Benzyloxycarbonyl-Phe-Arg-N-trifluoromethylcoumarinylamide is also a highly sensitive substrate for papain.