The function of coenzyme A in luminescence.

Abstract Firefly luciferin (C13H12N2S2O3) reacts with ATP to form active luciferin (apparently adenyl-luciferin) and pyrophosphate. The oxidation of active luciferin leads to light emission and adenyl-oxyluciferin, the latter compound eventually decomposes into adenylic acid and oxyluciferin (C13H10N2S2O3). Oxyluciferin is a potent inhibitor of the light reaction and once it has reacted with ATP and luciferase, the latter is incapable of catalyzing the oxidation of luciferin. Coenzyme A stimulates light emission by removing oxyluciferin from the enzyme surface. The evidence indicates that oxyluciferyl-CoA is formed, which can react non-enzymically with cysteine, glutathione or hydroxylamine to form the corresponding oxyluciferyl derivatives. Chromatographic, isotopic and fluorometric data are presented to support the above conclusions. Oxyluciferyl-CoA in the presence of luciferase can be split by adenylic acid and when excess pyrophosphate is added ATP and free oxyluciferin are formed. The incorporation of 14C-adenylic acid into ATP depends upon the presence of CoA in the reaction mixture. The importance of these various reactions for light emission and electron transport is discussed.