The Citric Acid Cycle

2nd Law of Thermodynamics

Carboxylic Acids and Derivatives

Enzymes

The hydrolysis of the thioester bond of succinyl CoA has sufficient negative free energy to be coupled with the phosphorylation of GDP. Among other possible uses, the GTP can later be used to generate ATP. (GTP is a nucleotide derivative analogous to ATP, except that the purine is guanine instead of adenine).