Membrane-anchoring subunit of succinate dehydrogenase (SDH) that is involved in complex II of the mitochondrial electron transport chain and is responsible for transferring electrons from succinate to ubiquinone (coenzyme Q). The heme b is bound between the two transmembrane subunits SDHC and SDHD. Carbohydrate metabolism; tricarboxylic acid cycle. Component of complex II composed of four subunits: the flavoprotein (FP) SDHA, iron-sulfur protein (IP) SDHB, and a cytochrome b560 composed of SDHC and SDHD. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Belongs to the cytochrome b560 family.