Coenzyme A - Wikipedia 
https://en.wikipedia.org/wiki/Coenzyme_A   
    "Coenzyme A (CoA, CoASH, or HSCoA) is a coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle. All genomes sequenced to date encode enzymes that use coenzyme A as a substrate, and around 4% of cellular enzymes use it (or a thioester, such as acetyl-CoA) as a substrate. "  

Contents

• 1 Biosynthesis

In all living organisms, Coenzyme A is synthesized in a five-step process that requires four molecules of ATP, from pantothenate and cysteine:^[2]

1. Pantothenate (vitamin B₅)
   

1. 
   
2. is phosphorylated to 4'-phosphopantothenate by the enzyme 
3. 
   
4. pantothenate kinase (PanK; CoaA; CoaX)

1. A cysteine

1. 
   
2. 
   
3.  is added to 4'-phosphopantothenate by the enzyme
   
4. 
   
5. phosphopantothenoylcysteine synthetase (PPCS; CoaB) to form
   
6. 
   
7. 4'-phospho-N-pantothenoylcysteine. 
   

1. PPC is decarboxylated to
   
2. 
   
3. 
   
4. 4'-phosphopantetheine by 
5. 
   
6. 
   
7. phosphopantothenoylcysteine decarboxylase (PPC-DC; CoaC)

1. 4'-phosphopantetheine is adenylylated to form dephospho-CoA by the enzyme
   
2. 
   
3. 
   
4. 
   
5. phosphopantetheine adenylyl transferase (PPAT; CoaD)
6. Finally, dephospho-CoA is phosphorylated to coenzyme A by the enzyme
   
7. 
   
8. 
   
9. dephosphocoenzyme A kinase (DPCK; CoaE). 
   

        ATP + dephospho-CoA ADP + CoA   

Enzyme nomenclature abbreviations in parentheses represent eukaryotic and prokaryotic enzymes respectively. In some plants and bacteria, including Escherichia coli, pantothenate can be synthesised de novo and is therefore not considered essential. 

• 2 Discovery of structure
• 3 Function
• 4 Non-exhaustive list of coenzyme A-activated acyl groups
• 5 Additional images
• 6 References
• 7 Bibliography