The percolation phenomenon usually observed at high temperatures occurs at room temperature in the presence of the protein. This process takes place at high water contents at a given cytochromecconcentration or at low water contents increasing the cytochromecconcentration. The increase in the water content in filled micelles induces a phase separation with two optically transparent phases. The upper phase mainly contains isooctane while the lower phase contains all the AOT, water and cytochrome.