STRUCTURALLY DISTINCT BACTERIAL LUCIFERASES

Bacterial luciferase catalyzes a bioluminescent oxidation of reduced flavin mononucleotide by molecular oxygen, the photon yield of the reaction being greatly stimulated by the presence of a long-chain aldehyde. Although luciferases from different bacterial strains have similar requirements, we have found a strain (designated as MAV) which, when compared with Photobacterium fischeri, has distinctive enzymatic differences in the quantitative responses to different reduced flavins and different aldehydes, in the pH activity profile and in the kinetics of light emission. Structurally this MAV luciferase also has apparent similarities to the Photobacterium fischeri luciferase but even more distinctive differences. The molecular weights of both are about 80,000 with two different subunits of nearly but not exactly equal size. The subunits are all distinctively different, judged both by their amino acid compositions and by the fact that no hybridization occurs between pairs from the different luciferases. It is assumed that the proteins are related and possess active-site structural similarities, studies of which should be of value in understanding the mechanism by which chemical energy is converted into light energy. © 1969, American Chemical Society. All rights reserved.