Fatty acyl-CoA ligase catalyzes the transfer of a free fatty acid to coenzyme A in the reaction below.
Fatty acid + ATP + CoASH <=> Fatty acyl-CoA + AMP + PPi (Figure 18.14)
Three separate enzymes with specificity for short, medium, and long chain fatty acids are used in the cell.
Long chain fatty acyl-CoA ligase is found in the endoplasmic reticulum and the outer mitochondrial membrane. It acts on fatty acids with chain lengths of 10 to 20 carbons.
The medium and short chain enzymes are found primarily in the mitochondrial matrix and prefer fatty acids of 4-12 carbons (medium) and acetate or propionate (short).
-Oxidation of Saturated Fatty Acid,
Synthesis of Long Chain Fatty Acids