Coenzyme A (CoA)

Coenzyme A (CoA) is a coenzyme derived from pantothenic acid (B5), cysteine, and ATP. It carries acyl groups (as thioesters) in metabolic reactions, most famously as acetyl-CoA. Acetyl-CoA is central to metabolism: it's the entry point to the Krebs cycle, the building block for fatty acid and cholesterol synthesis, and the acetyl donor for acetylation reactions.

The ratio of CoA to acetyl-CoA is an important metabolic indicator.

Metabolic Connections

Coenzyme A (CoA) connects to 7 other pathways.

Cofactors

ATP

ATP is used in CoA biosynthesis; acetyl-CoA metabolism produces ATP

Adenosine triphosphate - universal energy currency of cells. Requires magnesium for biological activity.

Neurotransmitters

Acetylcholine

Acetyl-CoA provides the acetyl group for acetylcholine synthesis

Neurotransmitter essential for memory, learning, attention, and muscle contraction. Synthesized from choline and acetyl-CoA.

Cell Membrane

Cholesterol

Acetyl-CoA is the building block for cholesterol synthesis

Essential sterol in cell membranes. Precursor to all steroid hormones, vitamin D, and bile acids.

Nutrient Groups

Fatty Acids

CoA is required for fatty acid synthesis and oxidation

Lipid building blocks; energy source via beta-oxidation; components of membranes; include saturated, mono, and polyunsaturated types.

Metabolic Cycles

Krebs Cycle

Acetyl-CoA enters the Krebs cycle for energy production

Central metabolic pathway (citric acid cycle) that generates electron carriers for ATP production and biosynthetic precursors.

B Vitamins

Vitamin B5 (Pantothenic Acid)

CoA is synthesized from pantothenic acid (B5)

Essential for CoA synthesis; required for fatty acid metabolism, steroid synthesis, and acetylcholine production.

Vitamin B5 (Pantothenic Acid)

B5 is a component of coenzyme A

Essential for CoA synthesis; required for fatty acid metabolism, steroid synthesis, and acetylcholine production.