Reactome | Carnitine synthesis

Carnitine synthesis

Stable Identifier

R-HSA-71262

DOI

10.3180/REACT_2125.1

Type

Pathway

Species

Homo sapiens

Compartment

cytosol, mitochondrial matrix

ReviewStatus

5/5

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Carnitine is required for the shuttling of fatty acids into the mitochondrial matrix and its deficiency is associated with metabolic diseases. It is abundant in a typical Western diet but can also be synthesized in four steps from trimethyllysine (generated in turn by the S-adenosyl-methionine-mediated methylation of lysine residues in proteins, followed by protein hydrolysis). The enzymes that catalyze the first three steps of carnitine synthesis, converting trimethyllysine to gamma-butyrobetaine, are widely distributed in human tissues. The enzyme that catalyzes the last reaction, converting gamma-butyrobetaine to carnitine, is found only in liver and kidney cells, and at very low levels in brain tissues. Other tissues that require carnitine, such as muscle, are dependent on transport systems that mediate its export from the liver and uptake by other tissues (Bremer 1983; Kerner & Hoppel 1998; Rebouche & Engel 1980; Vaz & Wanders 2002).

Literature References

PubMed ID	Title	Journal	Year
6770910	Tissue distribution of carnitine biosynthetic enzymes in man Engel, AG, Rebouche, CJ	Biochim Biophys Acta	1980
6361812	Carnitine--metabolism and functions Bremer, J	Physiol. Rev.	1983
11802770	Carnitine biosynthesis in mammals Vaz, FM, Wanders, RJA	Biochem J	2002
9706223	Genetic disorders of carnitine metabolism and their nutritional management. Hoppel, C, Kerner, J	Annu Rev Nutr	1998