carnitine metabolic process, CoA-linked

Definition

Target type: biologicalprocess

The chemical reactions and pathways involving carnitine, where metabolism is linked to CoA. [GOC:go_curators]

Carnitine metabolism is a crucial biological process involved in the breakdown and utilization of fatty acids as an energy source, particularly in tissues with high energy demands such as skeletal muscle, heart, and liver. This process involves the transport of long-chain fatty acids across the mitochondrial membrane, where they undergo beta-oxidation for ATP production. The key player in this process is carnitine, a quaternary ammonium compound synthesized from lysine and methionine. The carnitine shuttle system facilitates the transport of fatty acyl-CoA molecules from the cytoplasm into the mitochondrial matrix, where they can be oxidized. The process begins with the activation of fatty acids by the enzyme acyl-CoA synthetase, producing fatty acyl-CoA esters. The first step in the carnitine shuttle involves the transfer of the fatty acyl group from CoA to carnitine, catalyzed by carnitine palmitoyltransferase I (CPT-I) located on the outer mitochondrial membrane. This reaction forms acylcarnitine, which is then transported into the mitochondrial matrix by the carnitine-acylcarnitine translocase (CACT). Inside the mitochondrial matrix, carnitine palmitoyltransferase II (CPT-II) catalyzes the transfer of the fatty acyl group back to CoA, releasing carnitine. The fatty acyl-CoA is now ready for beta-oxidation, a process that involves sequential steps of oxidation, hydration, oxidation, and cleavage, yielding acetyl-CoA units, which enter the citric acid cycle for ATP production. The free carnitine is then transported back to the cytoplasm by CACT to facilitate further rounds of fatty acid transport. Overall, the carnitine metabolic process is essential for energy production from fatty acids, particularly during periods of fasting, exercise, or dietary fat intake. The process is tightly regulated by factors such as insulin, glucagon, and the availability of carnitine. Dysregulation of carnitine metabolism can lead to various metabolic disorders, such as carnitine deficiency and fatty acid oxidation disorders.'
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Proteins (1)

Compounds (1)