CYPRIDINA BIOLUMINESCENCE - LIGHT-EMITTING OXYLUCIFERIN-LUCIFERASE COMPLEX

Fluorescence of Cypridina oxyluciferin is greatly enhanced when it is bound to luciferase; the spectrum is thereby shifted, so that it corresponds precisely to the emission spectrum characteristic of the bioluminescent oxidation of luciferin. Thus the oxyluciferin-luciferase complex is the light-emitter. The binding is equimolar, with dissociation constant KD equal to 3 x 10-7 mole per liter. The molecular weight of the luciferase, according to three different methods, is between 52,000 and 57,000; molecular activities of luciferase for the bioluminescence reaction and for the hydrolysis of oxyluciferin are 1600 and 2 per minute, respectively.