Carnitine palmitoyltransferase-1 (CPT1), localized to the mitochondrial outer membrane, translocates fatty acids across the mitochondrial membranes and catalyzes the rate-limiting step of β-oxidation. There are three isoforms of this enzyme: CPT1A (liver), CPT1B (muscle), and CPT1C (brain). Deficiency of CPT1A results in an autosomal recessive mitochondrial fatty acid oxidation disorder. Studies have shown that physiological high blood glucose and insulin levels inhibit CPT1B activity in human muscle and therefore divert long-chain fatty acids toward storage in human muscle as triglycerides. Furthermore, mice deficient in CPT1C show less food intake and reduced body weight. These findings suggest that CPT1 may play a role in metabolic syndromes.
