Photoinduced enhancement of the tryptophan fluorescence of the enzyme in the luciferase — luciferin complex

An experiment providing evidence in support of the hypothesis that the bioluminescent reaction is dissociative in character was proposed and carried out. The processes occurring in the native bioluminescent system were modelled by the luciferase — luciferin complex. The experiment was performed in accordance with the pump-and-probe scheme involving probing by picosecond laser pulses and was based on the steady-state quenching of the intrinsic tryptophan fluorescence of luciferase when the latter is bound in a complex with luciferin. An increase in the intensity of the tryptophan fluorescence on photoexcitation of luciferin was regarded as confirmation of the hypothesis of the dissociation of the complex and it made it possible to estimate the rate of propagation of the corresponding conformational changes through the protein molecule.