Abstract: The invention provides assays for detecting and quantitating tissue factor and factor VIIa in simple and complex biological systems. The assays are performed by detecting and/or measuring the tissue factor cofactor activity and factor VIIa enzymatic activity using aminonapthalene-based fluorogenic substrates.

Abstract: The present invention encompasses compounds of formula I: ##STR1## and the pharmaceutically acceptable non-toxic salts thereof; wherein R.sub.1 is hydrogen, lower alkyl, alkenyl, alkynyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, or phenylalkyl;R.sub.2 is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, or phenylalkyl; orNR.sub.1 R.sub.2 forms a nitrogen heterocycle; andR.sub.3 is hydrogen, an amino acid or a peptide residue.These compounds may be employed as substrates in assays for determining proteolytic enzyme activity or as enzyme inhibitors. The invention also encompasses methods for determining proteolytic enzyme activity using the compounds of formula I.