Coelenterazine is the substrate for the enzymes Renilla luciferase, Gaussia luciferase and other luciferase enzymes. Marine organisms like squids, shrimps, fish and jellyfish use coelenterazine to produce spectacular bioluminescence (in analogy with insects which utilize firefly luciferine). Today, coelenterazine is used in numerous applications like immunoassays, ELISA, and protein based calcium indicators. The isolation and structure determination of coelenterazine was reported independently by two different groups in the seventies who discovered the molecule in sea pansy (Renilla reniformis) and in the cnidarian Aequorea victoria, respectively. Interestingly (PNAS 98 (20): 11148–51) it was also found that the luminescent jellyfish Aequorea victoria does not produce coelenterazine itself but it rather assimilates it through ingestion of small preys like shrimps and copepods.