Photinus pyralis is used to isolate the luciferase (Luc) gene.
It specifies the enzyme that catalyzes the ATP/oxygen-dependent oxidation of luciferin as a substrate.
As a result of this, light is produced.
The gene is used in highly sensitive tests for promoter activity as a reporter and protein targeting sequences, which use luminometers, liquid scintillation counter photomultipliers, X-ray film exposure, or sensitive camera film to quantify light emission.