Cytochrome C
Cytochrome C is released from a leaky mitochondria in apoptosis, from the intermembrane space to the cytosol. It activates caspase 9 within the cell. Caspase 9 then activates other caspases within the cell, amplifying the message of apoptosis [1].
It also plays a role in the electron transport chain, accepting electrons from complex III and donating them to complex IV.[2]
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