Coelenterazine is a luminophore found in aquatic organisms and is the substrate for many luciferase enzymes, including Renilla reniformis, Gaussia and aequorins. It is commonly used for bioluminescent calcium detection and the monitoring of reporter genes in BRET (Bioluminescence Resonance Energy Transfer), ELISA and HTS methods as well as chemiluminescent detection of superoxide anions and peroxynitrite in cells or tissues.