Catalysis by hemoproteins and their structural organization in reversed micelles of surfactants in octane

The cytochromes $\text{P-450}$ LM-2 and $\text{b}{}_5$ from rabbit liver microsomes have been entrapped into reversed micelles of surfactants in octane. The optimum conditions providing for the maximum stability of the hemoproteins have been found: pH and concentration of the buffer solution, the glycerol addition, the surfactant concentration, the [H₂O]/[surfactant] ratio and, finally, the reversed micelles composition including aerosol OT and its mixture with Triton X-45, Tween 20 and cetyltrimethylammonium bromide (CTAB). The transformation kinetics of the hemoproteins solubilized by detergents has been studied by monitoring the absorbance of hemoproteins in the Soret band region. Significant changes in tryptophan fluorescence of cytochrome $\text{b}{}_5$ and in CD spectra of myoglobin in reversed micelles and their dependence on the [H₂O]/[aerosol OT] ratio have been shown. The three hemoproteins in reversed micelles have been found to exhibit high catalytic activity with respect to their reaction with cumene hydroperoxide. The kinetic and spectral data reveal the structural transformations of the proteins entrapped into the micelles due to the interactions of the lumenal surface of the micelles and the protein molecule surface.