Catalytic oxidation of o-phenylenediamine by cytochrome c encapsulated in reversed micelles

Cytochrome c solubilized in reversed micelles formulated with di-2-ethylhexyl sulfosuccinate (AOT) has allowed to catalyze the oxidation of o-phenylenediamine (o-PDA) with hydrogen peroxide. The oxidative reaction did not occur effectively by cytochrome c in water. The nanostructural environment in reversed micelles seemed to perturb the three-dimensional structure of the active site of cytochrome c. The product obtained in reversed micelles had a specific absorption spectrum with the absorption peak at 720 nm, indicating a blue-colored solution, whereas common peroxidases such as horseradish peroxidase provided a yellow-colored product in water with the absorption peak at 420 nm. The difference in the oxidative products suggests that AOT molecules play an important role in the specificity of o-PDA oxidation. The dependency of the product species on the pH of the inner droplet in reversed micelles indicated that the specific oxidative product was prepared by electrostatic interaction with AOT molecules.