Figure 2.

Scheme illustrating how cytochrome c acts as a potent scavenger of superoxide whose loss may increase both matrix and extramitochondrial ROS. Cytochrome c loss restricts electron flow leading to an increase in the reduction state of the pool of ubiquinone, complex I and complex II. Moreover, the rate of anion superoxide oxidation by the pool of oxidized cytochrome c decreases secondary to its leak in the cytosol. These events lead to an excess of ROS production in the matrix and the IMS, thus sensitizing mPTP to calcium.