title: Fluorogenic substrates for chymotrypsin with 2-quinolinone derivatives as leaving groups.
abstract: Sensitive and convenient fluorometric assays for the determination of chymotrypsin have been developed by using the substrates Glt-Leu-Phe-NH-Meq, Glt-Phe-NH-FMeq and Glt-Leu-Phe-NH-FMeq, which have been synthesized utilizing the mixed anhydride method. The amidolytic activity of chymotrypsin was measured by the release of the highly fluorescent amine 7-amino-4-methyl-2-quinolinone (AMeq) or 7-amino-4-trifluoromethyl-2-quinolinone (AFMeq). The fluorescence properties of the synthesized substrates and the new fluorescent marker AFMeq were examined. Kinetic constants, as well as the maximum sensitivity for the hydrolysis of the new substrates, were determined. All new substrates permit a rapid and sensitive determination of chymotrypsin in a continuous assay system. As little as 0.7 ng of enzyme can be detected using the substrate Glt-Leu-Phe-NH-Meq, which is the most sensitive fluorogenic substrate thus far reported.
authors.affiliation: Department of Chemistry, University of Athens.
authors.forename: G
authors.initials: G
authors.lastname: Kokotos
authors.forename: R
authors.initials: R
authors.lastname: Geiger
authors.forename: C
authors.initials: C
authors.lastname: Tzougraki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002863:Chromogenic Compounds; D002918:Chymotrypsin / Q000378:metabolism*; D004151:Dipeptides / Q000138:chemical synthesis / Q000737:chemistry; D005453:Fluorescence; D005470:Fluorometry / Q000379:methods; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D015363:Quinolones / Q000138:chemical synthesis / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods; D013379:Substrate Specificity; D013552:Swine
chemical_list: D002863:Chromogenic Compounds; D004151:Dipeptides; D011804:Quinolines; D015363:Quinolones; C067689:7-glutaryl-phenylalaninamide-4-trifluoromethyl-2-quinolinone; C067690:7-glutaryl-leucyl-phenylalaninamide-4-trifluoromethyl-2-quinolinone; C067688:7-glutaryl-leucyl-phenylalaninamide-4-methyl-2-quinolinone; C067687:7-amino-4-methyl-2-quinolinone; D010649:Phenylalanine; C067686:7-amino-4-trifluoromethyl-2-quinolinone; D002918:Chymotrypsin