The best known activity of carnitine is its role as a transporter of long-chain fatty acids in the mitochondrial matrix, where fatty acids are converted into energy through the Beta-Oxidation process. L-Carnitine is used as a nutritional supplement. both in clinical and sports fields.
of its total carnitine, which on the whole corresponds to 25%.The endogenous synthesis takes place starting from the substrate TML (6-N-trimethylsine), which in turn derives from the methylation of the amino acid lysine. The TML is then hydroxylated into hydroxythmethyline (HTML) by means of trimoxylismine dioxygenase, which requires the presence of ascorbic acid and iron. HTML is then broken down by HTML aldolase (a pyridoxal phosphate that requires the enzyme), producing 4-trimethylaminobutyraldehyde (TMABA) and glycine. TMABA is subsequently dehydrogenated to gamma-butyrobetaine in a NAD + dependent reaction, catalyzed by TMABA dehydrogenase. Gamma-butyrobetaine is then hydroxylated by gamma-butyrobetaine hydroxylase (a binding enzyme of) into L-carnitine, which requires iron in the form of Fe2 +.
In summary:
- 6-N-trimethyllysine (TML) is obtained by methylation of lysine
- By means of trimoxylsyoxygenase, in the presence of iron and ascorbic acid (vitamin C), TML is hydroxylated into hydroxyithmethylline (HTML)
- By aldolase, HTML is broken down into 4-trimethylaminobutyraldehyde (TMABA) + glycine
- With the action of TMABA dehydrogenase and NAD + catalysis, TMABA is dehydrogenated into gamma-butyrobetaine
- Through the activity of gamma butyrobetaine hydroxylase, gamma-butyrobetaine is then hydroxylated into L-carnitine, which requires iron in the form of Fe2 +.
