Coenzyme A

Coenzyme A is a small molecule that transfers acyl groups in metabolism. Its reactive thiol group forms high-energy thioester bonds, including acetyl-CoA.

Thioester: A compound containing a carbon–sulfur bond in which sulfur is bonded to an acyl group. CoA carries acyl groups by forming thioester bonds at its terminal sulfur.
Pantothenic acid: A water-soluble B vitamin, also called vitamin B5, used to synthesize coenzyme A. Pantothenate supplies the central backbone of CoA.
Citric acid cycle: A cyclic pathway that oxidizes acetyl groups to carbon dioxide while capturing energy in reduced cofactors. Acetyl-CoA supplies the acetyl group that enters the cycle.
Acyl carrier protein: A protein that carries growing fatty-acid chains through a phosphopantetheine-linked thiol. It uses a CoA-like reactive arm but holds intermediates within fatty-acid synthesis.
Acetyl-CoA: A thioester of coenzyme A and an acetyl group that donates acetyl units in metabolism. This familiar CoA derivative delivers two-carbon units to pathways such as the citric acid cycle.
Cysteamine: A small molecule containing both an amino group and a reactive thiol group. Cysteamine forms the CoA tail that ends in the acyl-binding sulfur.
Fatty acid oxidation: The metabolic breakdown of fatty acids into acetyl-CoA and reduced electron carriers. This pathway generates acetyl-CoA by repeatedly removing two-carbon units.
Lipoamide: A disulfide-containing cofactor that carries acyl groups and transfers electrons in enzyme complexes. Lipoamide and CoA exchange acyl groups during oxidative decarboxylation reactions.
Acyl transfer: A chemical reaction that moves an acyl group from one molecule to another. CoA enables acyl transfer by accepting and donating groups through its thiol.
Adenosine diphosphate: A nucleotide consisting of adenine, ribose, and two phosphate groups. An ADP-like portion anchors the phosphopantetheine arm within CoA’s structure.

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