Ketone Bodies

Ketone bodies are a group of molecules that includes acetoacetate and D-ß-hydroxybutyrate.

During starvation or fasting, acetyl-coenzyme A is overproduced as fatty acids break down. Instead of being fed into the citric acid cycle, some acetyl-coenzyme A molecules are converted to ketone bodies in the liver. During starvation, ketone bodies become an important source of energy for the brain.

Fatty acids break down into acetyl-coenzyme-A, which is then broken down into acetoacetate and D-beta-hydroxybutyrate. The chemical structures of acetoacetate and D-beta-hydroxybutyrate are shown.
During starvation, fatty acids break down and acetyl-coenzyme A is overproduced. Some acetyl-coenzyme A is converted to ketone bodies (acetoacetate and D-ß-hydroxybutyrate).