Carnitine Biosynthesis Pathway L carnitine is primarily synthesized in the liver from the amino acids lysine and methionine through a series of four enzymatic reactions, with the liver and kidneys converting the precursor butyrobetaine into active Role of Carnitine Shuttle System in the Active Transport of Fatty Acyl Coa into the mitochondrial Carnitine metabolic disorders and novel clinical approaches: Mechanistic insights from deficiency management to liver and kidney disease treatment ScienceDirect Carnitine transport and fatty acid oxidation ScienceDirect