Luciferase Reverse Micellar Bioluminescence: Kinetics and Emission Spectra
Firefly luciferase is a hydrophobic enzyme that which catalyses the oxidation of luciferin by molecular oxygen and requires the enzymatic cofactors ATP and magnesium ions. This enzymatic reaction is accompanied by intense luminescence. Luciferase is generally considered a membrane-associated protein. Most of the current extensive knowledge of luciferase enzymology has been been carried out in aqueous systems in which the lifetime of bioluminescence following the injection of ATP is on the order of seconds. Therefore, the kinetics of its reaction in membrane-mimetic systems such as the colloidal reverse micelle system would be expected to be quite different. Following the initial report of Belyaeva et. al.1, we decided to investigate the effect of pH on the spectral and kinetic properties of the luciferase bioluminescence reaction in colloidal reverse micelles2 formed from the interaction of the nonionic surfactant Brij 96, water and cyclohexane. Previous aqueous luciferase investigations have shown that as the pH is decreased from 8.0, the bioluminescence emission maxima shifts from 562 nm, the same as observed in the in vivo bioluminescence, to > 600 nm, with a corresponding decrease in the bioluminescence quantum efficiency.
KeywordsNonionic Surfactant Reverse Micelle Intense Luminescence Bioluminescence Reaction Fast Decay Component
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