Succinate dehydrogenase is an important tetrameric protein involved in the citric acid cycle. It is localized to the inner mitochondrial membrane of cells. Succinate dehydrogenase makes up Complex II of the electron transport chain (ETC) and is responsible for the conversion of succinate to fumarate. This enzymatic reaction also generates a molecule of FADH2, harnessed by the ETC to make energy for the cell. SDHA, the flavoprotein subunit of the succinate dehydrogenase tetrameric complex, interacts with SDHB, SDHC, and SDHD in the complex.