Bruce R. Branchini
Department of Chemistry
New London, CT 06320
Bioluminescence is an enchanting process in which living organisms convert chemical energy into light. With the interesting exception of the photoproteins, in most bioluminescence systems light results from the oxidation of an organic substrate, a luciferin, catalyzed by an enzyme called a luciferase. In nature, there is an amazing diversity of organisms that emit light including bacteria, fungi, crustaceans, mollusks, fishes and insects. While the specific biochemistries of bioluminescence are diverse, all include an enzyme-mediated reaction between molecular oxygen and an organic substrate. It is likely too that all bioluminescence processes involve the formation and breakdown of a four-member ring peroxide or a linear hydroperoxide. An overview of the chemical and mechanistic aspects of a major bioluminescence process, that of the bioluminescent beetles, will be presented here.
Figure 1. The North American firefly Photinus pyralis.
Representing an estimated 3,000 species of luminous beetles (Coeleoptera), are three families: the true fireflies, click beetles, and glow-worms. Beginning approximately 50 years ago with the pioneering work of Johns Hopkins University scientists William McElroy, Emil White and Howard Seliger, basic research, mainly focused on the common North American firefly Photinus pyralis (Figure 1), has progressed toward a very good understanding of how light is produced by fireflies. It is anticipated that the availability of two Photinus pyralis luciferase crystal structures will advance the present understanding of the key structure-function relationships that account for the efficient enzyme-catalyzed emission of light in the firefly. In turn, the prospects are bright for the continued application of firefly bioluminescence to the already impressive list of medical and...