title: Homogeneous time-resolved fluorescence quenching assay (LANCE) for caspase-3.
abstract: In addition to kinases and G protein-coupled receptors, proteases are one of the main targets in modern drug discovery. Caspases and viral proteases, for instance, are potential targets for new drugs. To satisfy the current need for fast and sensitive high-throughput screening for inhibitors, new homogeneous protease assays are needed. We used a caspase-3 assay as a model to develop a homogeneous time-resolved fluorescence quenching assay technology. The assay utilizes a peptide labeled with both a luminescent europium chelate and a quencher. Cleavage of the peptide by caspase-3 separates the quencher from the chelate and thus recovers europium fluorescence. The sensitivity of the assay was 1 pg/microl for active caspase-3 and 200 pM for the substrate. We evaluated the assay for high-throughput usage by screening 9600 small-molecule compounds. We also evaluated this format for absorption/distribution/metabolism/excretion assays with cell lysates. Additionally, the assay was compared to a commercial fluorescence caspase-3 assay.
authors.affiliation: PerkinElmer Life Sciences/Wallac Oy, Turku, Finland. jarkko.kavinen@perkinelmer.com
authors.forename: Jarkko
authors.initials: J
authors.lastname: Karvinen
authors.forename: Pertti
authors.initials: P
authors.lastname: Hurskainen
authors.forename: Sujatha
authors.initials: S
authors.lastname: Gopalakrishnan
authors.forename: David
authors.initials: D
authors.lastname: Burns
authors.forename: Usha
authors.initials: U
authors.lastname: Warrior
authors.forename: Ilkka
authors.initials: I
authors.lastname: Hemmilä
mesh_terms: D001681:Biological Assay; D053148:Caspase 3; D020169:Caspases / Q000032:analysis* / Q000378:metabolism; D005063:Europium / Q000378:metabolism; D005453:Fluorescence
chemical_list: D005063:Europium; D053148:Caspase 3; D020169:Caspases