Luciferin () is a generic term for the light-emitting compound found in organisms that generate

bioluminescence Bioluminescence is the emission of light during a chemiluminescence reaction by living organisms. Bioluminescence occurs in multifarious organisms ranging from marine vertebrates and invertebrates, as well as in some Fungus, fungi, microorgani ...

. Luciferins typically undergo an

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

-catalyzed reaction with molecular oxygen. The resulting transformation, which usually involves breaking off a molecular fragment, produces an

excited state In quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Add ...

intermediate that emits light upon decaying to its

ground state The ground state of a quantum-mechanical system is its stationary state of lowest energy; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state ...

. The term may refer to molecules that are substrates for both luciferases and photoproteins.

Types

Luciferins are a class of small-molecule substrates that react with oxygen in the presence of a luciferase (an enzyme) to release

energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...

in the form of

light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– ...

. It is not known just how many types of luciferins there are, but some of the better-studied compounds are listed below. Because of the chemical diversity of luciferins, there is no clear unifying mechanism of action, except that all require molecular oxygen, The variety of luciferins and luciferases, their diverse reaction mechanisms and the scattered phylogenetic distribution indicate that many of them have arisen independently in the course of evolution.

Firefly

Firefly luciferin Firefly luciferin (also known as beetle luciferin) is the luciferin, precursor of the light-emitting compound, used for the firefly ( Lampyridae), railroad worm ( Phengodidae), starworm ( Rhagophthalmidae), and click-beetle ( Pyrophorini) biolumi ...

is the luciferin found in many Lampyridae species, such as '' P. pyralis''. It is the substrate of beetle luciferases ( EC 1.13.12.7) responsible for the characteristic yellow light emission from fireflies, though can cross-react to produce light with related enzymes from non-luminous species. The chemistry is unusual, as

adenosine triphosphate Adenosine triphosphate (ATP) is a nucleoside triphosphate that provides energy to drive and support many processes in living cell (biology), cells, such as muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all known ...

(ATP) is required for light emission, in addition to molecular

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

Snail

Latia luciferin is, in terms of chemistry, (''E'')-2-methyl-4-(2,6,6-trimethyl-1-cyclohex-1-yl)-1-buten-1-ol formate and is from the freshwater snail '' Latia neritoides''.EC 1.14.99.21
ORENZA: a database of ORphan ENZyme Activities, accessed 27 November 2009.

Bacterial

Bacterial luciferin is two-component system consisting of

flavin mononucleotide Flavin mononucleotide (FMN), or riboflavin-5′-phosphate, is a biomolecule produced from riboflavin (vitamin B2) by the enzyme riboflavin kinase and functions as the prosthetic group of various oxidoreductases, including NADH dehydrogenase, as ...

and a fatty aldehyde found in

bioluminescent bacteria Bioluminescent bacteria are Bioluminescence, light-producing bacteria that are predominantly present in sea water, marine sediments, the surface of decomposing fish and in the gut of marine animals. While not as common, bacterial bioluminescence ...

Coelenterazine

Coelenterazine Coelenterazine is a luciferin, a molecule that emits light after reaction with oxygen, found in many aquatic organisms across eight phyla. It is the substrate of many luciferases such as '' Renilla reniformis'' luciferase (Rluc), ''Gaussia'' lu ...

is found in radiolarians,

ctenophore Ctenophora (; : ctenophore ) is a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), and they ar ...

cnidarian Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

brittle star Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomot ...

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

s, chaetognaths, fish, and shrimp. It is the prosthetic group in the protein aequorin responsible for the blue light emission.

Dinoflagellate

Dinoflagellate The Dinoflagellates (), also called Dinophytes, are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered protists. Dinoflagellates are mostly marine plankton, but they are also commo ...

luciferin is a

chlorophyll Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words (, "pale green") and (, "leaf"). Chlorophyll allows plants to absorb energy ...

derivative (i. e. a

tetrapyrrole Tetrapyrroles are a class of chemical compounds that contain four pyrrole or pyrrole-like rings. The pyrrole/pyrrole derivatives are linked by ( or units), in either a linear or a cyclic fashion. Pyrroles are a five-atom ring with four carbon ...

) and is found in some

dinoflagellate The Dinoflagellates (), also called Dinophytes, are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered protists. Dinoflagellates are mostly marine plankton, but they are also commo ...

s, which are often responsible for the phenomenon of nighttime glowing waves (historically this was called

phosphorescence Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluor ...

, but is a misleading term). A very similar type of luciferin is found in some types of euphausiid shrimp.

Vargulin

Vargulin Vargulin, also called Cypridinid luciferin, Cypridina luciferin, or Vargula luciferin, is the luciferin found in the ostracod '' Cypridina hilgendorfii'', also named '' Vargula hilgendorfii''. These bottom dwelling ostracods emit a light stream ...

is found in certain

ostracod Ostracods, or ostracodes, are a Class (biology), class of the crustacean, Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 33,000 species (only 13,000 of which are extant taxon, extant) have been identified,Brandão, S.N.; Antoni ...

s and deep-sea fish, to be specific, '' Poricthys''. Like the compound coelenterazine, it is an imidazopyrazinone and emits primarily blue light in the animals.

Fungi

Foxfire is the bioluminescence created by some species of fungi present in decaying wood. While there may be multiple different luciferins within the kingdom of

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

, 3-hydroxy

hispidin Hispidin is a natural substance. It can also be synthesized. Hispidin 4-''O''-β-D-glucopyranoside can be found in ''Pteris ensiformis'' whereas hispidin derivatives, such as phellibaumins, can be found in the edible mushroom '' Inonotus xerantic ...

was determined to be the luciferin in the fruiting bodies of several species of fungi, including '' Neonothopanus nambi'', '' Omphalotus olearius'', '' Omphalotus nidiformis'', and '' Panellus stipticus''.

Usage in science

Luciferin is widely used in science and medicine as a method of ''in vivo'' imaging, using living organisms to non-invasively detect images and in molecular imaging. The reaction between luciferin substrate paired with the receptor enzyme luciferase produces a catalytic reaction, generating bioluminescence. This reaction and the luminescence produced is useful for imaging such as detecting tumors from cancer or capable of measuring

gene expression Gene expression is the process (including its Regulation of gene expression, regulation) by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, proteins or non-coding RNA, ...

References

External links

* {{cite web , url = http://www.lifesci.ucsb.edu/~biolum/chem/detail1.html , title = Major luciferin types , date = 2009-01-09 , work = The Bioluminescence Web Page , publisher =

University of California, Santa Barbara The University of California, Santa Barbara (UC Santa Barbara or UCSB) is a Public university, public Land-grant university, land-grant research university in Santa Barbara County, California, United States. Tracing its roots back to 1891 as an ...

, access-date = 2009-03-06 Biological pigments Bioluminescence Fluorescent dyes Luciferins