photoprotein

In molecular biology, photoproteins are a type of enzyme produced by bioluminescent organisms. They add to the function of the luciferins whose usual light-producing reaction is catalyzed by the enzyme luciferase.

==History== thumb|upright|The marine worm Chaetopterus was the source of the first photoprotein to be discovered. The term photoprotein was first used to describe the unusual chemistry of the luminescent system of Chaetopterus (a marine Polychaete worm). This was meant to distinguish them from other light-producing proteins because these do not exhibit the usual luciferin-luciferase reaction.