The apoptosome is a 1-megadalton holoenzyme complex consisting of cytochrome c and Apaf-1. Following the intrinsic pathway of apoptosis, the release of mitochondrial cytochrome c into the cytoplasm results in binding with Apaf-1. Seven pairs of this subunit then come together to form a circular wheel-like structure. This complex in turn binds and activates procaspase-9 to activate which proceed to activate other apoptotic caspases. Because of the apoptosome’s major role in cell death and proliferation, inhibitors for Apaf-1 and cytochrome c can have potentially beneficial uses in studying the apoptotic process.