Coelenterazine

Coelenterazine is a luciferin, a light-emitting biomolecule that serves as a substrate for luciferases or as a constituent of photoproteins, including aequorin. The oxidation of coelenterazine to coelenteramide is accompanied by emission of blue light (emission maximum, 460-470 nm). Luciferase-mediated oxidation of coelenterazine or a derivative is used as an energy donor, typically to a form of green or yellow fluorescent protein, in bioluminescent resonance energy transfer studies. Alternatively, the calcium-mediated release of coelenterazine from aequorin, followed by non-enzymatic oxidation of this compound, results in bioluminescence. As light emission depends on both calcium and cellular redox status, this reaction is used to non-fluorescently detect changes in calcium level and redox status.

Coelenterazine is the luciferin, the light-emitting molecule, found in many aquatic organisms across seven phyla. It is the substrate of many luciferases such as Renilla reniformis luciferase (Rluc), Gaussia luciferase (Gluc), and photoproteins, including aequorin, and obelin. Coelenterazine was used: For Aequorin assays; For measuring the intracellular calcium concentration in response to ionomycin or PMA using aequorin in COS-7 cells2;. In Bioluminescence imaging for analysing the presence of virus-dependent luciferase activity. Luminophore of the aequorin complex which is oxidized by oxygen to illuminate at 465 nm when Ca2+ binds to the complex; used to measure Ca2+ concentration in cells with high sensitivity and large dynamic range.