The Coenzyme A molecule - rotatable in 3 dimensions

Coenzyme A is used in the transfer of acyl groups in carbohydrate and fatty acid metabolism.

There is a thiol (=SH) group at one end of the Coenzyme A molecule, so it is sometimes referred to as CoASH. This can form thioesters with the acyl groups

These groups - acetyl (CH₃COO-), succinyl (^-OOC-C₂H₄-COO-) - are 2-carbon and 4-carbon sections effectively derived from acetic (ethanoic) acid and succinic acid.

Acetyl Coenzyme A is formed following the breakdown of pyruvate in the link reaction between glycolysis and the Krebs cycle, and Succinyl Coenzyme A is formed following the breakdown of α- ketoglutarate within the Krebs cycle itself.

The Coenzyme A molecule is built up from three sections:

• adenosine (adenine and ribose) - with a single phosphate group at the 3' position and two phosphate groups at the 5' position
• a central section derived from pantothenic acid (vitamin B5)
• the terminal section derived from the sulphur-containing amino acid cysteine