Bioluminescence: mechanism and mode of control of scintillon activity.

Subcellular particles, termed scintillons, isolated from the luminescent dinoflagellate Gonyaulax, emit light when the pH is lowered from 8 to 5.7. The capacity to emit a second flash is regained by incubation of scintillons with the low molecular weight luciferin from Gonyaulax. This compound was previously demonstrated to be the substrate in the bioluminescent reaction catalyzed by a soluble luciferase isolated from the same cell. A model of the scintillon is presented that involves soluble elements structured within a membrane-bound particle.