Luciferase is a generic term for a group of oxidative enzymes used in bioluminescence. Firefly (Photinus pyralis) and bacterial luciferase enzymes are commonly used in assay systems such as cell viability assays, reporter gene assays, and for in vivo imaging. Bacterial luciferases are flavoenzymes composed of two subunits each encoded by the luxA and luxB genes, while the firefly luciferase is a single polypeptide specified by the luc gene (1). Firefly luciferase (theoretical molecular weight: 61 kDa) oxidizes the substrate luciferin to oxyluciferin in a bioluminescent reaction requiring Mg2+ and ATP (2,3). This reaction produces a flash of yellow-green light with an emission peak around 560nm that can be detected by a luminometer (3). Firefly luciferase has become one of the more widely used reporter proteins and is an excellent tool for the study of gene expression, given that the amount of light emitted is directly proportional to luciferase activity (4).
The luciferase assay is fast and sensitive, differentiating itself from the CAT (chloramphenicol acetyltransferase) assay because it does not require a radioactive substrate.
1. Eun, H. (1996). Marker/Reporter enzymes. Enzymology Primer for Recombinant DNA Technology, 567-645. doi:10.1016/b978-012243740-3/50011-9
2. McNabb, D. S., Reed, R., & Marciniak, R. A. (2005). Dual luciferase assay system for rapid assessment of gene expression in Saccharomyces cerevisiae. Eukaryotic Cell, 4(9), 1539-1549. doi:10.1128/ec.4.9.1539-1549.2005
3. Fraga, H. (2008). Firefly luminescence: A historical perspective and recent developments. Photochemical & Photobiological Sciences, 7(2), 146-158. doi:10.1039/b719181b
4. Younes, A., Lukyanenko, Y. O., Lyashkov, A. E., Lakatta, E. G., & Sollott, S. J. (2011). A bioluminescence method for direct measurement of phosphodiesterase activity. Analytical Biochemistry, 417(1), 36-40. doi:10.1016/j.ab.2011.05.036