'''Coenzyme A''' ('''CoA''', '''CoASH''', or '''HSCoA''') is a [[coenzyme]], notable for its role in the [[Fatty acid metabolism#Synthesis|synthesis]] and [[Fatty acid metabolism#.CE.B2-Oxidation|oxidization]] of [[fatty acid]]s, and the oxidation of [[pyruvic acid|pyruvate]] in the [[citric acid cycle]]. It is adapted from [[cysteamine]], [[pantothenic acid|pantothenate]] and [[adenosine triphosphate]].
Coenzyme A is synthesized in a five-step process from pantothenate:
# [[Pantothenate]] is phosphorylated to 4'-phosphopantothenate by the enzyme [[pantothenate kinase]]
# A cysteine is added to 4'-phosphopantothenate by the enzyme [[phosphopantothenoylcysteine synthetase]] to form 4'-phospho-N-pantothenoylcysteine (PPC)
# PPC is decarboxylated to 4'-phospho[[pantetheine]] by [[phosphopantothenoylcysteine decarboxylase]]
# 4'-phospho[[pantetheine]] is adenylylated to form dephospho-CoA by the enzyme [[phosphopantetheine adenylyl transerase]]
# Finally, dephospho-CoA is phosphorylated using ATP to coenzyme A by the enzyme [[dephosphocoenzyme A kinase]].