The isolation of catalytic components required for cell-free fungal bioluminescence

Two fractions have been isolated from luminous molds, both of which are necessary for light emission. The activity of one fraction, the supernatant of a 198,000 × g centrifugation, is heat labile, nondialyzable and ammonium sulfate precipitable, thus implying that it may be proteinaceous in nature. This fraction is thought to catalyze a reaction in which reduced diphosphopyridine nucleotide (DPNH) acts as an electron donor to an unknown constituent which is subsequently utilized in the actual light reaction. The second fraction, whose activity is also thought to be enzymic in nature, is the pellet obtained from the same centrifugation. This fraction catalyzes the actual light reaction and thus contains the enzyme that has classically been referred to as luciferase. Kinetic evidence suggests that the second fraction is functional in the oxidation of the unknown constituent mentioned above. The biological implications of these findings are discussed.