Fatty Acid Synthase

Synonyms

FAS; FASN

Definition

Fatty acid synthase is a key enzyme which regulates the de novo biosynthesis of long-chain fatty acids.

Characteristics

Structure and Function

Fatty acid synthase (FAS) is a key enzyme that regulates the de novo biosynthesis of long-chain fatty acids from acetyl-CoA and malonyl-CoA in the presence of NADPH. There are two types of FAS. FAS II, found in prokaryotes, plants, and mitochondria, consists of an acyl carrier protein (ACP) and seven structurally independent monofunctional enzymes. Each of these enzymes is encoded by a separate gene that produces a unique protein which catalyzes a single step in fatty acid synthesis. Mammalian FAS, named FAS I, consists of two identical multifunctional polypeptides. Each monomer of FAS I contains seven distinct catalytic domains starting from the N-terminal. These catalytic domains including β-ketoacyl synthase (KS), malonyl/acetyltransferase (MAT), dehydrase (DH), enoyl reductase (ER),