Bioluminescence Biochemistry

Bioluminescence is chemistry more efficient than any lightbulb. Nearly all photon output; near-zero heat. Fish either produce their own luciferin (intrinsic) or house symbiotic bacteria that do (extrinsic). Coelenterazine - the luciferin found in shrimp, jellyfish, and many fish - was the source of green fluorescent protein (GFP), now the workhorse of biomedical microscopy.

Luciferin + oxygen + ATP → oxyluciferin + light. Different species use different luciferins (coelenterazine, dinoflagellate luciferin). Enzymes and cofactors vary. Colour ranges from blue-green (most) to red (dragonfish).

Luciferin, luciferase, coelenterazine, aequorin, GFP (Green Fluorescent Protein).

GFP won the 2008 Nobel Prize in Chemistry. Bioluminescence tags let researchers track gene expression, protein localisation, and cell fate in living organisms.

The GFP gene from a jellyfish is now expressed in mice, fish, plants, and human cell lines - allowing scientists to literally light up cellular processes across biology.