K2 Fatty acid breakdown

Fatty acid breakdown (also called (3-oxidation) brings about the oxidation of long-chain fatty acids with the production of energy in the form of ATP. The fatty acids are converted into their acyl CoA derivatives and then metabolized by the removal of two-carbon acetyl CoA units from the end of the acyl chain. 

Fatty acid breakdown occurs in the cytosol of prokaryotes and in the mitochondrial matrix of eukaryotes. The fatty acid is activated by forming a thioester link with CoA before entering the mitochondria. 

The inner mitochondrial membrane is not permeable to long-chain acyl CoA derivatives and so these are transported into the mitochondria as carnitine derivatives by carnitine /acyl carnitine translocase. 

Fatty acid breakdown involves a repeating sequence of four reactions  

Thiolysis by a second CoA molecule to form acetyl CoA and an acyl CoA shortened by two carbon atoms. 

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