Luciferin

Luciferins (from the Latin lucifer, "light-bringing" ) are a class of light-emitting biological pigments found in organisms capable of bioluminescence.

Types of luciferin
Luciferins are a class of small-molecule substrate each for their corresponding protein enzyme luciferase. Luciferins are oxidized in the presence of the enzyme luciferase to produce oxyluciferin and energy in the form of light. There are five general types of luciferins.



Firefly luciferin
Firefly luciferin is the luciferin found in fireflies. It is the substrate of luciferase (EC 1.13.12.7) Johns Hopkins University synthesized luciferin, the substance which lights the tail of the firefly, furthering research on ATP, the primary energy source in biological action (1962).

Bacterial luciferin
Bacterial luciferin is a type of luciferin found in bacteria, some squid and fish. It consists of a long-chain aldehyde and a reduced riboflavin phosphate.

Dinoflagellate luciferin
Dinoflagellate luciferin is a chlorophyll derivative and is found in dinoflagellates, which are often responsible for the phenomenon of nighttime ocean phosphorescence. A very similar type of luciferin is found in some types of euphausiid shrimp.

Vargulin
Vargulin is found in certain deep-sea fish; specifically, ostracods and Poricthys. It is an imidazolopyrazine.



Coelenterazine
Coelenterazine is found in radiolarians, ctenophores, cnidarians, squid, copepods, chaetognaths, fish and shrimp. It is the light-emitting molecule in the protein aequorin.