Carnitine

carnitine [′kär·nə‚tēn]

(biochemistry)

C₇H₁₅NO₃α-Amino-β-hydroxybutyric acid trimethylbetaine; a constituent of striated muscle and liver, identical with vitamin B_T.

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Carnitine 

betaine-γ-amino-β-oxybutyric acid, (CH₃)₃NCH₂CH(OH)CH₂CO₂⁻, a crystalline compound with basic properties; dissolves readily in water and alcohol. Its molecular mass is 161.21, and its melting point, 195°-197°C (with decomposition).

Carnitine is primarily found in animal muscle, from which it was first extracted by V. S. Gulevich (1905); it is also found in bacteria and plants. It takes part in fatty exchange within an organism by acting as a carrier of fatty acid radicals through the membranes of the mitochondria. These membranes are impermeable to activated fatty acids (compounds with coenzyme A). With the aid of carnitine, therefore, fatty acids enter the scope of activity of the oxidizing enzymes localized within the mitochondria. Carnitine apparently also participates in the reverse transport of fatty acids. It is an essential dietary constituent and a growth factor in certain insects; therefore it is considered to be a vitamin (vitamin B_T).