Cytosolic delivery of cytochrome c conjugates induces apoptosis at nanomolar levels through a caspase-3-dependent pathway.

Cytochrome c (CytC) is conjugated with a small molecule TG6 to give TG6-CytC, which is directly delivered into cytosol, triggering the release of endogenous CytC from mitochondria, and inducing a caspase-3-dependent apoptosis with an IC 50 down to 2.4 nM. This work shows an efficient strategy for intracellular protein delivery.