What compound is responsible for transporting fatty acids to the mitochondria for entry into the Krebs cycle?

Carnitine plays a crucial role in the transportation of fatty acids into the mitochondria, which is essential for their oxidation and subsequent entry into the Krebs cycle. Fatty acids, being hydrophobic, cannot cross the mitochondrial membrane directly. Instead, they must first be converted to acyl-CoA in the cytosol where Coenzyme A is involved, but the actual transport across the mitochondrial membrane requires carnitine.

Once the fatty acids form acyl-CoA, carnitine binds to them, forming acylcarnitine. This acylcarnitine is then able to cross the inner mitochondrial membrane via specific transport proteins. Once inside the mitochondria, the acyl group is transferred back to CoA, regenerating acyl-CoA, which can then enter the Krebs cycle for energy production.

Knowing the specific functions of the other compounds helps clarify their roles in metabolism but highlights how carnitine is uniquely positioned in the fatty acid transport process. Coenzyme A is important for activation of fatty acids, Acetyl CoA is a product of fatty acid metabolism, and alpha-lipoic acid functions primarily as an antioxidant and cofactor in certain enzymatic reactions, rather than in the transport of fatty acids.