Patent ID: 8071328

Claim:
A luminescent assay method to detect one or more proteases comprising: a) combining a luciferase and an amino-modified luciferin or a carboxy-terminal protected derivative; b) contacting a sample containing one or more proteases with the combined luciferase and amino-modified luciferin or a carboxy-terminal protected derivative thereof of step (a) to form a mixture, wherein the modification comprises the covalent linkage of a substrate for the protease to the amino group of aminoluciferin or the derivative thereof by a peptide bond, wherein the protease cleaves the substrate at the peptide bond in the mixture, and c) detecting luminescence in the mixture, thereby detecting the presence of one or more proteases in the sample, wherein the luminescent assay is more sensitive than a corresponding assay with a conjugate comprising a fluorophore covalently linked to the substrate or a functional equivalent thereof.