Conversion of Succinyl Co-A to succinate has a strongly negative free energy of hydrolysis of its thioester bond (ΔG° = –36 kJ/mol). In the next step of the citric acid cycle, the energy released in the breakage of this bond is used to drive the synthesis of a phosphoanhydride bond in either GTP or ATP, and succinate is also formed in this process.

The enzyme that catalyzes this reversible reaction is called either succinyl Co-A synthetase or succinic thiokinase; both names indicate the participation of a nucleoside triphosphate in the reaction.