succinate dehydrogenase complex assembly factor 2; Required for insertion of FAD cofactor into SDHA, the catalytic subunit of succinate dehydrogenase (SDH). SDH is involved in complex II of the mitochondrial electron transport chain and is responsible for transferring electrons from succinate to ubiquinone (coenzyme Q). In is unclear whether it participates in the chemistry of FAD attachment (enzymatic function) or acts as a chaperone that maintains SDHA in a conformation that is susceptible to autocatalytic FAD attachment (166 aa)