This enzyme can be inhibited by malonyl CoA, the first committed intermediate produced during fatty acid synthesis.

[8][9] Both isoforms are integral proteins of the mitochondrial outer membrane through two transmembrane regions in the peptide chain.

[10] It is polytopic, with both the N- and C-termini exposed on the cytosolic aspect of the OMM, with a short loop linking the two transmembrane domains protruding into the mitochondrial inter-membrane space.

[14] An important structural difference between CPT1 and CPT2, CRAT and carnitine octanoyltransferase (COT) is that CPT1 contains an additional domain at its N-terminal consisting of about 160 amino acids.

[7] A different mechanism has been proposed that suggests that a catalytic triad composed of residues Cys-305, His-473, and Asp-454 carries out the acyl-transferring step of catalysis.

The carnitine palmitoyltransferase system is an essential step in the beta-oxidation of long chain fatty acids.

By acting as an acyl group acceptor, carnitine may also play the role of regulating the intracellular CoA:acyl-CoA ratio.

These decreased malonyl-CoA levels in turn prevent inhibition of CPT1, causing an ultimate increase in fatty acid oxidation.

[22] This rare disorder confers risk for hepatic encephalopathy, hypoketotic hypoglycemia, seizures, and sudden unexpected death in infancy.

The increased levels of malonyl-CoA caused by hyperglycemia and hyperinsulinemia inhibit CPT1, which causes a subsequent decrease in the transport of long chain fatty acids into muscle and heart mitochondria, decreasing fatty acid oxidation in such cells.

The shunting of LCFAs away from mitochondria leads to the observed increase in FFA levels and the accumulation of fat in skeletal muscle.