L-Carnitine — the key to energy metabolism

摘要

The first studies of carnitine took place over 100 years ago, when it was discovered in muscle extracts (Gulewitsch and Krinberg, 1905). Since then its chemical structure, biosynthesis and natural sources have been the object of many studies. Even now, after so many years, the study of L-carnitine continues to be extremely interesting, with the ongoing discovery of new functions and metabolic processes where L-carnitine is involved in one way or another.L-carnitine is biosynthesized in the liver and kidneys from lysine and methionine. Although lysine and methionine supply the basic framework for this, carnitine synthesis cannot be influenced by the lysine and methionine provided by diet. This is becausetrimethyllysine (TML), the first metabolite for carnitine synthesis, is only available after degradation of proteins within the context of the protein turnover. This signifies that L-carnitine is produced endogenously from protein degradation and not from dietary amino acids.