Discovery of a series of 2-phenylnaphthalenes as firefly luciferase inhibitorsElectronic supplementary information (ESI) available: 1H NMR, 13C NMR and HPLC spectra for all compounds; absorbance spectra of compound 5. See DOI: 10.1039/c5ra12886b

As the most convenient and efficient bioluminescence system, the firefly luciferase/luciferin complex has been widely used in life science research and high-throughput screening (HTS). Nonetheless, the interpretation of firefly luciferase-based assay data is often complicated by the occurrence of "false positives," in part because firefly luciferase (Fluc) is subject to direct inhibition by HTS compounds that might inadvertently act as inhibitors of its catalytic site. Here we report a series of 2-phenylnaphthalenes as Fluc inhibitors with suitable potency both in vitro and in vivo . Besides, our compound 5 showed significant systemic inhibition in transgenic mice. Enzymatic kinetics study reveals that compound 5 is competitive for substrate aminoluciferin and noncompetitive for the second substrate ATP. Furthermore, compound 5 exhibited good performance as a quenching agent in a dual-luciferase reporter assay. We anticipate that these Fluc inhibitors will contribute to the broader utilization of bioluminescence in life science research while circumventing or at least reducing the number of "false positives". A series of 2-phenylnaphthalenes as firefly luciferase inhibitors are reported. The most potent compound 5 showed good systemic inhibition in transgenic mice. Kinetic assay indicated 5 is competitive for aminoluciferin and noncompetitive for ATP.