This enzyme is involved in both cholesterol synthesis as well as in ketone body synthesis.HMG CoA reductase is the rate-limiting enzyme of the cholesterol synthesis.HMG CoA lyase is the enzyme involved in ketone body synthesis.Thiolases are also known as acetyl-Coenzyme A acetyltransferases (ACAT), which are enzymes which conve two units of acetyl-CoA to acetoacetyl CoA in the mevalonate pathway. Thiolases are ubiquitous enzymes that have key roles in many vital biochemical pathways, including the beta-oxidation pathway of fatty acid degradation and various biosynthetic pathways.