ω-3 Arachidonic acid is a rare PUFA found in trace amounts in dietary sources. ω-3 Fatty acids are known to be essential for infant growth and development and they protect against heart disease, thrombosis, hypertension, as well as inflammatory and autoimmune disorders. In human platelet membranes, ω-3 arachidonic acid inhibits arachidonoyl-CoA synthetase with a Ki of 14 µM. It also inhibits arachidonoyl-CoA synthetase in calf brain extracts with an IC50 value of about 5 µM. ω-3 Arachidonic acid ethyl ester is a more lipophilic form of the free acid.