Carnitine transporter and carnitine acyltransferase

The **carnitine transporter** (notably, the sodium-dependent organic cation transporter OCTN2, gene SLC22A5, and the mitochondrial carnitine-acylcarnitine translocase/CACT, gene SLC25A20) is essential for cellular uptake and mitochondrial import of carnitine, which is required for the transfer of long-chain fatty acids into mitochondria for β-oxidation. **Carnitine acyltransferases** are a family of enzymes that catalyze the reversible transfer of acyl groups between CoA and carnitine, forming acylcarnitines that are transported across mitochondrial membranes by the carnitine transport system. The main members, **carnitine palmitoyltransferases 1 and 2** (CPT1, CPT2), facilitate the transport and metabolism of long-chain fatty acids and are critical in energy production via mitochondrial β-oxidation. **Carnitine acetyltransferase** (CrAT) and **carnitine octanoyltransferase** (CrOT) have similar functions but act on short- and medium-chain substrates, respectively. Deficiencies or dysfunction in any component of this system can result in clinically significant metabolic diseases and represent potential therapeutic targets for conditions such as type 2 diabetes, obesity, and some cardiovascular disorders.

Other names

Carnitine transporter (main gene: SLC22A5, also called OCTN2)Carnitine-acylcarnitine translocase (CACT, gene: SLC25A20)Carnitine palmitoyltransferase 1 (CPT1)Carnitine palmitoyltransferase 2 (CPT2)Carnitine acetyltransferase (CrAT)Carnitine octanoyltransferase (CrOT)

Inhibition of fatty acid oxidation by inhibiting CPT1 (energy shift from lipids to carbohydrates, relevant in angina, heart failure) Supplementation of L-carnitine increases cellular uptake via transporter, enhances β-oxidation in deficiency states