Subcellular Localization : Mitochondrion intermembrane space. Note=Loosely associated with the inner membrane.
Protein Function : Electron carrier protein. The oxidized form of the cytochrome c heme group can accept an electron from the heme group of the cytochrome c1 subunit of cytochrome reductase. Cytochrome c then transfers this electron to the cytochrome oxidase complex, the final protein carrier in the mitochondrial electron-transport chain.