The Z factor is a widely-used parameter to indicate the power of a given assay method to distinguish between negative and positive controls. In general, an assay is considered valid if the is Z factor at the maximal response concentration (EC100) is > 0.5.7 In the present experiment, the Z factor at the EC50 was 0.54-0.66. This Z factor at a concentration lower than the EC100 indicates a powerful assay.
The proteasome sensor is well-suited for high-throughput screening of candidate modulators of proteasome activity and the assay can easily be run in Molecular Devices microplate fluorometers.
1. Press release by the Royal Swedish Academy of Sciences, 6 October 2004 (http:// nobelprize.org/chemistry/laureates/2004/ index.html).
2. Glickman, M.H. and Adir, N. (2004) The Proteasome and the delicate balance between destruction and rescue. PLoS Biol 2(1):e13 DOI:10.1371/journal.pbio.0020013.
4. Clontechniques April 2004 (http://www. bdbiosciences.com/clontech/archive/ APR04UPD/Living_Colors.shtml).
5. Clontechniques April 2003 (http://www. bdbiosciences.com/clontech/archive/ APR03UPD/pdf/ProteasomeSensor.pdf).
6. Zhang, L., Song, L., Parker, E.M. Calpain inhibitor I increases beta-amyloid peptide production by inhibiting the degradation of the substrate of gamma-secretase. Evidence that substrate availability limits beta-amyloid peptide production. J Biol Chem 1999 Mar 26;274(13):8966-72.
7. Zhang, J.H., Chung, T.D., Oldenburg, K.R. A simple statistical parameter for use in evaluation and validation of high throughput sc