Final answer:
Executioner caspases become maximally activated through interactions with cytochrome C and adaptor proteins, which assist in converting procaspases to active caspases during apoptosis.
Step-by-step explanation:
Maximal activation of executioner caspases requires interactions with cytochrome C and adaptor proteins. In the process of apoptosis, cytochrome C is released from the mitochondria as a peripheral membrane protein, existing in an equilibrium between membrane-bound and unbound states. Once in the cytosol, cytochrome C binds to adaptor proteins, which then aggregate to form a complex. This cytochrome C-adaptor complex has a high affinity for procaspases and their binding triggers an allosteric change in the enzyme, activating the caspases to initiate cellular self-digestion.