The synthesis of fatty acids in mammalian systems can be considered as a two-stage process, both stages requiring acetyl-Coenzyme A (acetyl CoA) and both employing multifunctional proteins (multienzyme complexes):
stage 1: involves preparation of the key precursor malonyl-CoA by the acetyl CoA carboxylase,
stage 2: involves elongation of the fatty acid chain (in 2-carbon increments) by fatty acid synthase.
