Luciferin

Definition
noun, plural: luciferins
A substrate for the enzyme luciferase, and whose reaction generates bioluminescence
Supplement
Some organisms are capable of producing and emitting light through natural biochemical reaction. Bioluminescence pertains to the capability of an organism to produce and emit light. One of the ways by which bioluminescent organisms emit light is through the luciferin-luciferase reaction system. In this system, luciferin serves as a substrate of luciferase. Luciferase is the enzyme that acts on the oxidation of luciferin. This ultimately results in the release of a photon. This is what is observed in fireflies. Accordingly, there are two main steps involved in firefly’s luciferin-luciferase reaction. The first step is luciferin reacting with ATP. This results in the production of luciferyl adenylate and PPi. The second step is the luciferyl adenylate reacting with oxygen (O₂) resulting in the production of oxyluciferin in and AMP. The oxidation of luciferyl adenylate produces oxyluciferin in an electronically excited state and in order to return to its ground state it has to release photon (or light). The luciferin of the firefly is one of the well-known types of luciferin. The other forms of luciferins are vargulin of bioluminescent ostracods and Poricthys, coelenterazine of bioluminescent radiolarians, ctenophores, cnidarians, etc., bacterial (Photorhabdus) luciferin, etc.
Word origin: Latin lucifer (“light-bringer”)
Chemical formula: C₁₁H₈N₂O₃S₂
See also:

• luciferase
• bioluminescence