Carnitine shuttle system ()

Carnitine shuttle system Overview

The **fatty acid mitochondrial transport system** refers collectively to the multi-step process and associated protein machinery responsible for importing long-chain fatty acids from the cytosol into the mitochondrial matrix, where they undergo β‐oxidation. This process is essential because long-chain fatty acids cannot cross the inner mitochondrial membrane unaided. The primary mechanism is known as the **carnitine shuttle**, which involves several key steps and proteins: 1. **Activation:** Long-chain fatty acids are first activated in the cytosol by long-chain acyl-CoA synthetase to form acyl-CoA[4]. 2. **CPT1:** On the outer mitochondrial membrane, carnitine palmitoyltransferase I (CPT1) catalyzes transfer of an acyl group from CoA to carnitine, forming acyl-carnitine[4][8]. 3. **Translocation:** Acyl-carnitines are transported across the inner mitochondrial membrane by carnitine-acylcarnitine translocase (CAC/SLC25A20), exchanging them with free carnitine moving out[4][8]. 4. **CPT2:** On the matrix side of the inner membrane, CPT2 transfers back the acyl group from carnitine onto CoA to regenerate intramitochondrial acyl-CoA ready for β‐oxidation[4][8]. This coordinated action enables efficient delivery of substrates required for ATP production via β‐oxidation and subsequent entry into citric acid cycle. **Note on correctness:** The term “fatty acid mitochondrial transport system” does *not* refer to a single molecular target or receptor but rather describes an integrated pathway involving multiple distinct enzymes and transporters—primarily CPT1, CAC/SLC25A20, and CPT2—as well as accessory molecules like L-carnitine[7]. Therefore it is not considered a canonical therapeutic target itself; instead its components can be individually targeted or studied. If you require structured information about one specific protein within this pathway—such as “Carnitine palmitoyltransferase 1” or “Carnitine-acylcarnitine translocase”—please specify that particular molecule so that detailed data can be provided accordingly[4][7][8].

Mechanism of Action

Biological Functions

Safety Considerations