Question

The body oxidizes macronutrients for ATP production. Which catabolic pathway does it produce ketone bodies?

Answer 1

• Ketone bodies are metabolic products , which are produced in excess during excessive breakdown of fatty acids.
• Aceto acetate , acetone and beta hydroxy butyrate are collectively known as ketone bodies.
• Ketone bodies are water soluble and energy yielding .
• In normal man , concentration of ketone bodies in the blood is usually less than 3mg/100ml.

KETOGENESIS

1. Two Acetyl-CoA is joined to form Acetoacetyl-CoA with the help of thiolase enzyme.
2. Acetoacetyl-CoA is converted to beta hydroxy beta methyl glutaryl CoA (HMG-CoA), with the help of HMG-CoA synthase.
3. beta hydroxy beta methyl glutaryl CoA (HMG-CoA) is converted to Aceto acetate with the help of HMG-CoA Lyase.
4. Aceto acetate is converted to acetone( by non enzymatic decarboxylation) and to D-Beta hydroxy butyrate( by D-Beta hydroxy butyrate dehydrogenase enzyme.)