From The Merck Index, 10th edition: “Light emission in the American firefly, Photinus pyralis, has been shown to involve the interaction of magnesium ion, oxygen, ATP [the coenzyme adenosine triphosphate], the enzyme luciferase, and the oxidizable substrate luciferin.” Photinus is one genus of the firefly family Lampyridae.
In 1957, B. Bitler and W. D. McElroy at Johns Hopkins University isolated 9 mg of luciferin from ≈15,000 Japanese fireflies (Luciola cruciata). McElroy, E. H. White, and co-workers elucidated its structure and synthesized it in the lab in the early1960s.
Crystalline luciferin is fluorescent; it absorbs 327-nm UV radiation and emits visible light at 530 nm. Light emitted from fireflies ranges from green (510 nm) to red (670 nm). Luciferin has been used in an assay for ATP, with a sensitivity for the coenzyme in solution as low as 10–11 M.
The name luciferin comes from the Latin lucifer, or light-bearer. Lucifer, of course, in Christian tradition is the name of Satan before his fall. So if it’s warm enough to see fireflies on Halloween, you can blame it on climate change and the devil.
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