CPT1A is the key enzyme in the carnitine-dependent transport across the mitochondrial inner membrane and its deficiency results in a decreased rate of fatty acid beta-oxidation.  CPTI plays a crucial role in mitochondrial β-oxidation of long-chain fatty acids, initiating fatty acid transport from cytoplasm into mitochondrion, which is a rate-limiting step in the metabolic pathway. This process is essential for energy production, particularly in tissues that rely heavily on fatty acid oxidation, such as heart and skeletal muscle. CPTI exists in two isoforms: CPT1A, predominantly expressed in liver, and CPT1B, specifically found in muscle tissues. Membrane-bound CPTI is reversibly inhibited by malonyl-coenzyme A, highlighting regulatory mechanisms that control fatty acid metabolism.