Luciferin is the generic term for the molecules that emit light when reacted with luciferase enzymes. Fireflies use a specific type of luciferin derived from oxyluciferin, which has a high quantum yield and produces green to yellow light.
Luciferase is the generic term for the enzymes that catalyze the oxidation of luciferin, resulting in light emission. Fireflies use a specific type of luciferase called firefly luciferase, which belongs to the acyl-CoA synthetase family and has a high specificity for firefly luciferin.
ATP is the energy currency of the cell and is required for the luciferase reaction. ATP provides the activation energy and the phosphate group for the formation of the luciferyl-adenylate intermediate, which then reacts with oxygen to produce oxyluciferin and light.
Adenosine triphosphate (ATP)
Magnesium is a cofactor for the luciferase enzyme and is essential for its activity and stability. Magnesium binds to the luciferase and facilitates the binding of ATP and luciferin.
Oxygen is the final electron acceptor in the luciferase reaction and is necessary for the oxidation of the luciferyl-adenylate intermediate to oxyluciferin and light. Oxygen also regulates the light emission by acting as a substrate and an inhibitor of the enzyme.