Acetoacetate (AcAc) is a β-ketoacid formed in the mitochondria by the condensation of two molecules of acetyl-CoA. AcAc is either enzymatically reduced to 3-hydroxybutyrate or decarboxylated to produce acetone. Ketone bodies (AcAc, 3-HB, and acetone) are used as alternate source of energy in the absence of glucose. Excess ketone bodies are observed in type I diabetes, alcoholism, or starvation.
