Induces apoptosis through a caspase dependent pathway. Reduces mitochondrial membrane potential. Does not translocate to the nucleus upon induction of apoptosis. Ubiquitous. Expressed in bone marrow, cerebral cortex, liver, ovary, thymus, thyroid gland and tongue (at protein level). The Rieske domain induces apoptosis. Belongs to the FAD-dependent oxidoreductase family.