In beta-oxidation of fatty acids carnitine is required for
Role of Carnitine Fatty acids are activated in the cytoplasm, but the beta-oxidation is in mitochondria. So transpo of fatty acids through the mitochondrial membrane is essential. The long chain fatty acyl CoA cannot pass through the inner mitochondrial membrane. Therefore a transpoer, carnitine is involved in transfer of fatty acids. Carnitine is beta-hydroxy- gamma-trimethyl ammonium butyrate, (CH3)3-N+-CH2-CHOH-CH2-COOH. It is synthesised from lysine and methionine in liver and kidney. Carnitine Acyl Transferase The enzyme carnitine acyl transferase-I (CAT-I) will transfer the fatty acyl group to the hydroxyl group of carnitine to form acyl carnitine The reaction occurs on the cytosolic side of inner mitochondrial membrane. : Translocase A protein translocase will carry the acylcarnitine across the membrane to the matrix of mitochondria. On the matrix side of the membrane, another enzyme, carnitine acyl transferase-II (CAT-II) will transfer the acyl group back to coenzyme A molecule. Carnitine is returned to the cytosolic side by the translocase.Ref: DM Vasudevan - Textbook of Biochemistry, 8th edition, page no: 131