Photinus pyralis firefly luciferase (PpyLuc)

Photinus pyralis firefly luciferase is a 62 kDa monomeric enzyme derived from the common North American firefly that catalyzes the oxygenation of D-luciferin in the presence of Mg2+ and ATP to produce light (UniProt P08659). This bioluminescent reaction is highly efficient and has made the enzyme a cornerstone of modern biotechnology, where it serves as a sensitive reporter for gene regulation, protein-protein interactions, and ATP levels (PubMed: 19233030). Although it is not a therapeutic target for treating human diseases, it is a frequent nuisance target in drug discovery because many small molecules can bind to and inhibit the enzyme, creating artifacts in high-throughput screening (HTS) (PubMed: 19575519). One notable example is Ataluren (PTC124), which was discovered using a luciferase reporter assay and was later found to interact directly with the luciferase protein, complicating the interpretation of its activity (PubChem). Consequently, researchers must use orthogonal assays to distinguish between true biological activity and luciferase interference. The enzyme's structure consists of a large N-terminal domain and a smaller C-terminal domain that sandwich the substrates during the catalytic cycle (PubMed: 8703071).

Other names

Luciferin 4-monooxygenase (ATP-hydrolyzing)Firefly luciferaseLucPpyLuc

The enzyme catalyzes the two-step oxidation of D-luciferin. First, it reacts with ATP to form a luciferyl-adenylate intermediate; second, this intermediate reacts with molecular oxygen to produce oxyluciferin, CO2, AMP, and light at a peak wavelength of approximately 560 nm (UniProt P08659; PubMed: 8703071).