Cytochrome c

Cytochrome c is a relatively small (~12 kDa) polycationic mitochondrial protein. It was first identified as an electron shuttle in the electron transport chain. In healthy cells, the protein is found in the mitochondrial intermembrane space; it is associated with the inner mitochondrial membrane cardiolipin (CL), a lipid which comprises approximately 9-13 mol% (18-25% by weight) of that membrane. In 1996, Liu et al. found that the release of cytochrome c from the mitochondrial intermembrane space into the cytosol can induce apoptosis and that addition of exogenous cytochrome c to the cytosol causes a similar response.

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