β-Oxidation is the main way our bodies break down fats to get energy. The speed of this process depends on how much unprocessed fat (not stored) is in our cells. This amount is influenced by the fat levels in our blood. When there’s more circulating fat in the blood, it boosts fat breakdown in tissues that can use it for energy, like muscles. However, the brain doesn’t use this type of fat for energy.
During times like starvation, long exercise sessions, or when we don’t have enough carbs, these circulating fats become a crucial energy source.
Before starting the β-oxidation process, the fat is changed into a CoA form.
Fatty acid+ATP+CoA→acyl-CoA+AMP+PPi
This process is sped up by a certain enzyme found in cells called cytosolic acyl-CoA synthase. There are many types of these enzymes, each designed to work with different lengths of fatty acid chains.
The breakdown of fatty acids happens inside a part of the cell called the mitochondrial matrix. To get there, the fatty acids, which are in the form of fatty acyl-CoA, must pass through two layers of the mitochondrial membrane. This membrane doesn’t let through fatty acids or fatty acyl-CoAs with chains longer than 12 carbons. However, fatty acids with shorter chains can get through both layers. For the medium and long chains, a special method involving carnitine is needed to move them across the membranes. This process relies on specific forms of an enzyme called carnitine palmitoyl transferase (CPT) found on the outer and inner parts of the mitochondrial membrane.
Also Check: