Activation of fatty acids

Fatty acid activation occurs in the cytosol, on the outer mitochondrial membrane immediately after their entry into the cell. Without the activation, it is impossible to consider the involvement of their molecules in metabolism. Activation then simultaneously maintains their steady concentration gradient (analogous to glucose phosphorylation - see glycolysis). The principle of fatty acid activation is the ester linkage of a fatty acid binding molecule to the SH-group of coenzyme A via acyl-Coenzyme A synthetase (fatty acid thiokinase):


 * MK + ATP + HS&minus;CoA → acyl&minus;CoA + AMP + 2 Pi

The activation of the fatty acid actually passes off in two stages. First, acyl adenylate (acyl-AMP) is formed and in the second phase AMP is exchanged for coenzyme A.