luciférases

Luciferases, or luciférases in French, are enzymes that catalyze the light-emitting oxidation of a luciferin substrate, producing bioluminescence. The light emission typically requires molecular oxygen and, in many systems, energy input in the form of ATP. The reaction is utilized by diverse organisms for signaling, predation, or camouflage, and the term refers to the enzyme itself while the light is the bioluminescent signal.

Different luciferases use different substrates and cofactors. Firefly luciferase (from Photinus pyralis) oxidizes D-luciferin in the presence of ATP and Mg2+, yielding oxyluciferin and a photon in the green–yellow range (roughly 550–570 nm). Renilla reniformis and Gaussia spp. luciferases use coelenterazine and oxygen, producing blue to cyan light around 480 nm without ATP. Bacterial luciferase (LuxAB) uses FMNH2 and a long-chain aldehyde with oxygen, emitting blue-green light near 490 nm; some bacterial systems also include enzymes to supply substrates.

Because of their sensitivity and quantitative output, luciferases are widely used as reporter enzymes in molecular biology. Assays measure light emitted after substrate addition to reflect promoter activity or gene expression. In vivo imaging employs substrate delivery to living organisms, enabling longitudinal studies of biological processes. Engineered variants include brighter enzymes, altered emission spectra, secretion signals, and split luciferases for protein interaction assays.

Beyond basic assays, luciferases have been adapted for dual-luciferase formats to normalize signals or monitor multiple pathways. The corresponding genes are expressed in plasmids or integrated into cells or organisms for research, biotechnology, and increasingly clinical diagnostics. Their applications rely on careful considerations of substrate delivery, biocompatibility, and assay design.