Peroxidative catalytic behavior of cytochrome c solubilized in reverse micelles

Abstract

Solubilization of horse heart cytochrome c into reverse micelles, a self-assembled nanostructure composed of sodium di-2-ethylhexyl sulfosuccinate (AOT), enhances the peroxidase activity in the presence of hydrogen peroxide. The catalytic activity of cytochrome c hosted in reverse micellar solution is 10-fold higher than that in water, and which depends on Wo, a molar ratio of water to AOT, and pH in aqueous droplets. In addition, the fluorescence intensity based on the tryptophan residue and the visible absorption identifying the axial Met 80-Fe bond imply that the reverse micellar solubilization induces the cleavage of the heme crevice and thus enables the formation of peroxidase-like peroxide-heme complexes. These results suggest that cytochrome c solubilized in reverse micelles provides a homogeneous catalyst as peroxidase available in organic media.