Luciferins

Types

Bioluminescent systems are not evolutionarily conserved. Luciferins share no obvious sequence homology. Because of the chemical diversity of luciferins, there is no clear unifying mechanism of action, except that all require molecular oxygen. Despite this, luciferins occur across 17 different phyla and at least ~700 genera. It seems they were often “invented” evolutionarily; phylogenetic studies show that luciferin-luciferase systems have over 30 independent origins. Emitted colors range from blue to red (400–700 nm), with blue hues most common and red emissions rare. This makes sense considering the majority of bioluminescent organisms live in the ocean where blue light penetrates water most effectively. It is not known just how many types of luciferins there are, but some of the better-studied compounds are listed below.