Acetoacetyl-coenzyme A (acetoacetyl-CoA) is a precursor to HMG-CoA in the isoprenoid pathway. It is reversibly converted to acetyl-CoA by acetoacetyl-CoA thiolase in the mitochondria. Acetoacetyl-CoA thiolase (T2) deficiency results in a build-up of ketone bodies leading to intermittent ketoacidosis. Acetoacetyl-CoA is also an intermediate in the microbial biosynthesis of polyhydroxybutyrate.
