Question

Under conditions of starvation, acetyl- CoA, instead of being degraded in the citric acid cycle, is converted to acetone and 3-hydroxybutyrate, compounds called ketone bodies that the brain can use as a temporary fuel. Show how the ketone bodies are formed.

Acetone 3- hydroxybutyrate

Short answer

The answer is,

acetone

3-hydroxybutyrate

Reaction

Step-by-step solution

Explanation

The Claisen condensation between two molecules of acetyl- CoA forms acetoacetyl- CoA, when hydrolyzed, forms acetoacetate. The acetoacetate undergoes decarboxylation to form acetone or it can be reduced to 3-hydroxybutyrate.

Explanation

The reaction for the synthesis of acetoacetate is as given below.

Reaction

The reaction for the synthesis of acetone and 3- hydroxyl butyrate from acetyl- CoA is given below.

acetone

3-hydroxybutyrate

Reaction