ABSTRACT
Fatty acid synthesis involves the condensation of two-carbon units, in the form of acetyl coenzyme A (CoA), to form long hydrocarbon chains in a series of reactions. These reactions are carried out on the fatty acid synthase complex using NADPH as reductant. The fatty acids are covalently linked to acyl carrier protein (ACP) during their synthesis. The enzymes for introducing double bonds into the acyl chain are also present on the cytosolic surface of the SER. Fatty acids are synthesized in the cytosol, but acetyl CoA is produced from pyruvate in the mitochondria. In prokaryotes, each of the reactions of fatty acid synthesis is catalyzed by a separate enzyme. The synthesis of fatty acids takes place when carbohydrate and energy are plentiful and when fatty acids are scarce. Acetyl CoA carboxylase is also subject to hormonal regulation.
