Electron-transferring-flavoprotein dehydrogenase in the inner mitochondrial membrane accepts electrons from electron-transfer flavoprotein which is located in the mitochondrial matrix and reduces ubiquinone in the mitochondrial membrane. The protein is synthesized as a 67kD precursor which is targeted to mitochondria and processed in a single step to a 64kD mature form located in the mitochondrial membrane. Deficiency in electron-transferring-flavoprotein dehydrogenase have been demonstrated in some patients with type II glutaricacidemia.