Cytochrome c protein (Cyt c)

Cytochrome c protein is a small, highly conserved, water-soluble heme protein located in the mitochondrial intermembrane space, where it plays a central role as an electron carrier in the respiratory chain by transferring electrons from complex III (cytochrome bc1 complex) to complex IV (cytochrome c oxidase), ultimately supporting ATP synthesis. It consists of about 104 amino acids, contains a covalently-bound heme group, and has a distinctive structure involving five α-helices with a characteristic CXXCH motif for heme binding. Upon mitochondrial outer membrane permeabilization, cytochrome c is released into the cytosol, where it acts as a major pro-apoptotic factor by activating caspase enzymes, thereby regulating cell death pathways. Its essentiality in energy metabolism, role in apoptosis, and high level of evolutionary conservation make it a key molecule in both physiology and disease research.

Other names

Cytochrome cCyt cC-type cytochrome

Induction of apoptosis (agents may promote cytochrome c release from mitochondria, leading to activation of caspases) Electron transfer disruption (toxins/drugs inhibit mitochondrial complexes, leading to functional blockade of cytochrome c’s electron shuttling) Oxidative stress modulation (agents may influence cytochrome c’s peroxidase activity)