Chapter 3: Progress and Perspectives on Bioluminescence: from Luminous Organisms to Molecular Mechanisms

McElroy's discovery of the requirement for ATP in firefly light emission in 1947 marked the onset of biochemical characterizations of many other bioluminescence systems over the subsequent decades, notably bacteria, fungi, dinoflagellates, cypridinids, coelenterates and mollusks, which are described. These, along with many other less-well characterized luminous systems, arose independently in evolution and thus use different luciferins and luciferases. Apparent exceptions to this generalization and their explanations are discussed, along with the nature of photoproteins, which are considered to represent aluciferase reaction intermediate in one case and a chemiluminescence in several others. Luciferins should be defined as luciferase substrates, which after reaction give rise to the species that is responsible for light emission. In cases where there are two substrates, only one is the luciferin. Thus, ATP in the firefly and aldehyde in the bacteria are not luciferins.