The rapid accumulation of sequence data and powerful protein engineering techniques providing large mutant libraries have greatly heightened interest in efficient methods for biochemical characterization of proteins. Herein is reported a continuous assay for screening of enzymatic activity. The assay is developed and tested with the model enzymes haloalkane dehalogenases and relies upon a fluorescent change of a derivative of 8-hydroxypyrene-1,3,6-trisulphonic acid due to the pH drop associated with the dehalogenation reactions. The assay is performed in a microplate format using a purified enzyme, cell-free extract or intact cells, making the analysis quick and simple. The method exhibits high sensitivity with a limit of detection of 0.06 mM. The assay is successfully validated with gas chromatography and then applied for screening of 12 haloalkane dehalogenases with the environmental pollutant bis(2-chloroethyl) ether and chemical warfare agent sulfur mustard. Six enzymes exhibited detectable activity with both substrates. The within-day variability of the assay for five replicates (n = 5) was 21%.

Faculty of Science Loschmidt Laboratories Centre for Toxic Compounds in the Environment RECETOX and Department of Experimental Biology Masaryk University Brno 625 00 Czech Republic

Faculty of Science Loschmidt Laboratories Centre for Toxic Compounds in the Environment RECETOX and Department of Experimental Biology Masaryk University Brno 625 00 Czech Republic International Clinical Research Center St Anne's University Hospital Pekarska 53 Brno 656 91 Czech Republic Enantis Ltd Kamenice 34 Brno 625 00 Czech Republic

References provided by Crossref.org