Scintillons have been extensively purified from L. polyedra by centrifugation, and these purified scintillon preparations contain luciferase and luciferin binding protein as the only detectable protein components. The amount of luciferase, LBP and luciferin all vary over the course of a daily (circadian) period, as do the number of scintillons in the cell. These observations suggest that the circadian control of bioluminescence involves a daily synthesis and degradation of luciferase and LBP. When synthesized, these two proteins aggregate together and migrate to the vacuole membrane where LBP binds luciferin and the scintillons acquires an ability to produce light upon stimulation.