Firefly Bioluminescence: A Mechanistic Approach of Luciferase Catalyzed Reactions

Luciferase is a general term for enzymes catalyzing visible light emission by living organisms (bioluminescence). The studies carried out with Photinus pyralis (firefly) luciferase allowed the discovery of the reaction leading to light production. It can be regarded as a two-step process: the first corresponds to the reaction of luciferase's substrate, luciferin (LH2), with ATP-Mg2+ generating inorganic pyrophosphate and an intermediate luciferyl-adenylate (LH2-AMP); the second is the oxidation and decarboxylation of LH2-AMP to oxyluciferin, the light emitter, producing CO2, AMP, and photons of yellow-green light (550-570 nm). In a dark reaction LH2-AMP is oxidized to dehydroluciferyl-adenylate (L-AMP). Luciferase also shows acyl-coenzyme A synthetase activity, which leads to the formation of dehydroluciferyl-coenzyme A (L-CoA), luciferyl-coenzyme A (LH2-CoA), and fatty acyl-CoAs. Moreover luciferase catalyzes the synthesis of dinucleoside polyphosphates from nucleosides with at least a 3'-phosphate chain plus an intact terminal pyrophosphate moiety. The LH2 stereospecificity is a particular feature of the bioluminescent reaction where each isomer, D-LH2 or L-LH2, has a specific function. Practical applications of the luciferase system, either in its native form or with engineered proteins, encloses the analytical assay of metabolites like ATP and molecular biology studies with luc as a reporter gene, including the most recent and increasing field of bioimaging. (C) 2008 IUBMB