The mitochondrial respiratory Complex II (CII) is one of key enzymes of cell energy metabolism. linking the tricarboxylic acid (TCA) cycle and the electron transport chain (ETC). CII reversibly oxidizes succinate to fumarate in the TCA cycle and transfers the electrons. produced by this reaction to the membrane quinone pool. https://www.roneverhart.com/Ryukyu-Kobujutsu-Buki-Jutsu-Vol-2-DVD-with-Kiyoshi-Yogi/