Fatty Acid Oxidation: Lipid Metabolism and Its Contribution to Energy Generation

Fatty acid oxidation is a crucial biochemical process responsible for the breakdown of lipids to generate energy in the form of ATP. This metabolic pathway primarily occurs in the mitochondria and involves several enzymatic reactions.

Overview of Lipid Metabolism

Lipids, primarily triglycerides, serve as a rich energy source. Their metabolism begins with lipolysis, where triglycerides are hydrolyzed into glycerol and free fatty acids. These fatty acids then enter the β-oxidation pathway.

Fatty Acid Transport and Activation

• Fatty acids are activated in the cytoplasm via conversion to acyl-CoA.
• Carnitine shuttle transports long-chain fatty acyl-CoA into the mitochondria.

Beta-Oxidation Pathway

Once inside the mitochondria, fatty acids undergo sequential enzymatic reactions:

• Oxidation by acyl-CoA dehydrogenase.
• Hydration of enoyl-CoA.
• Oxidation of hydroxyacyl-CoA.
• Thiolysis to generate acetyl-CoA.

Acetyl-CoA then enters the Krebs cycle for further ATP generation.

Clinical Significance

Defects in fatty acid oxidation can lead to metabolic disorders such as medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. Proper fatty acid metabolism is essential for maintaining energy balance, especially during fasting and exercise.