Coelenterazine F is a light-emitting molecule that has been shown to emit light when it binds to cytosolic Ca2+. In addition, it can be used in the detection of Ca2+ changes. The molecular structure consists of two disulfide bonds and a reactive cysteine residue that can form covalent bonds with other molecules. This reaction releases energy in the form of light. Coelenterazine F has been shown to produce fluorescence resonance energy transfer (FRET) with luciferase, which is a reconstituted protein complex that emits light when oxidized by coelenterazine F. Coelenterazine F has also been shown to induce pro-inflammatory cytokines, such as IL-6 and TNF-?, which are involved in inflammatory response.