Emits blue light flashes with a wavelength of 475 nm during the night phase. dinoflagellate luciferin + O2 = H(+) + H2O + hnu + oxidized dinoflagellate luciferin Regulated by pH: upon acidification, at a pH of 6.3, dinoflagellate luciferin is released from luciferin-binding protein LBP, allowing the interaction between Dinoflagellate luciferase and its substrate luciferin. Localizes in scintillons, specialized organelles formed as outpocketings from the cytoplasm into the acidic vacuole. Composed of 3 homologous Luciferase domains: each of the individual domains are most active at pH 6.3, and there is very little activity at pH 8.0. Dinoflagellate luciferase mediates much of the bioluminescence in ocean surface waters. Belongs to the calycin superfamily. Luciferase family.