Acetyl-CoA C-acyltransferase

The final step of beta oxidation is the cleavage of 3-ketoacyl CoA by the thiol group of another molecule of CoA. This reaction is catalyzed by Acetyl-CoA C-acyltransferase (or Β-ketothiolase). The thiol is inserted between C-2 and C-3, which yields an acetyl CoA molecule and an acyl CoA molecule, which is two carbons shorter.