coelenterazine

Coelenterazine is a luciferin, a small, hydrophobic molecule used by many marine organisms to generate bioluminescence. It acts as the substrate in oxidative reactions catalyzed by luciferases, producing light, typically in the blue region of the spectrum.

Bioluminescence mechanisms vary by system. In aequorin-based systems, Ca2+-activated aequorin consumes coelenterazine and oxidizes it to coelenteramide, emitting blue light around 470 nm. In Renilla luciferase and related enzymes, coelenterazine is directly oxidized by the luciferase to yield blue light near 480 nm. The overall reaction releases carbon dioxide as a byproduct.

Distribution and biosynthesis vary among organisms. Coelenterazine is found in a wide range of marine life, including jellyfish, copepods, and other cnidarians and crustaceans. Some species synthesize it, while others acquire it through diet. In the laboratory, coelenterazine is frequently produced synthetically or purchased commercially to fuel bioluminescent assays.

Applications and derivatives. Coelenterazine is widely used in molecular biology as a reporter substrate, notably with Renilla luciferase in luciferase-based assays and with aequorin for calcium signaling measurements. Derivatives of coelenterazine have been developed to modify brightness, stability, or emission properties, expanding its utility in imaging and analytical contexts.

Chemistry and handling. Coelenterazine is sensitive to light, oxygen, and pH changes; fresh preparation is preferred, and it is typically stored under appropriate conditions, often dissolved in organic solvents for use in assays.