Role of molecular oxygen in the bioluminescence of the firefly squid, Watasenia scintillans

The bioluminescence system in the “firefly squid,” Watasenia scintillans, is described. The light-emitting components consist of luciferin (coelenterazine disulfate), a membrane-bound luciferase, ATP, Mg2+, and molecular oxygen. A hypothetical scheme is proposed for the light-emitting reaction.