Patent ID: 8329425

Claim:
A method for quantitative or qualitative measuring chloramphenicol in a sample, comprising the steps of: (a) contacting a mutant chloramphenicol acetyltransferase (CAT)/fluorophore-linked chloramphenicol complex with an amount of a sample to be tested for the presence of chloramphenicol; and (b) determining the presence of the chloramphenicol in the sample based on the fluorescence intensity of the fluorophore-linked chloramphenicol after displacement from the mutant CAT/fluorophore-linked chloramphenicol complex by the chloramphenicol present in the sample; wherein the mutant CAT comprises at its active site at least one reductive amino acid residue, and wherein the reductive amino acid residue suppresses the fluorescence of the fluorophore-linked chloramphenicol when present in the mutant CAT/fluorophore-linked chloramphenicol complex.