- Paese produttoreGrecia
L-Carnitine is present as a natural constituent in human tissues. In humans, the physiological metabolic requirements are met both by the consumption of food, containing carnitine and the endogenous synthesis in the liver and kidneys from lysine with methionine, serving as the methyl donor. Only the L-isomer is biologically active, playing an essential role in lipid metabolism as well as in the metabolism of ketone bodies as branched-chain amino acids. Carnitine transports long-chain acyl groups from fatty acids into the mitochondrial matrix, so they can be broken down through β-oxidation to acetyl CoA to obtain usable energy via the Krebs cycle; with the same mechanism, it stimulates the activity of pyruvate dehydrogenase and in skeletal muscle the oxidation of branched-chain amino acids. L-Carnitine is thus involved, directly or indirectly in several pathways, so that its availability should be an important factor, controlling not only the oxidative utilisation of fatty acids and ketone bodies but also that of glucose and some amino acids.