Carnitine is linked to acyl groups transported into the mitochondria for oxidation (Figure 18.15). Acyl-CoAs in the cytoplasm are converted to acyl-carnitine derviatives by action of carnitine acyltransferase I on the outer portion of the mitochondrial inner membrane. A translocase carries the acyl-carnitine into the mitochondria. Once inside the mitochondrial matrix, carnitine is replaced on the acyl group by CoASH. The acyl-CoA then is free to go through oxidation or elongation.