Acyltransferases

Acyltransferases are a broad group of enzymes that catalyze the transfer of an acyl group from one molecule to another. In most cases the acyl donor is an acyl-CoA or an acyl carrier protein (acyl-ACP), and the acceptor is an alcohol, amine, or lipid moiety, resulting in esters, amides, or other acylated products. They are classified within EC 2.3.x.x, reflecting their role in transferring acyl groups.

In lipid metabolism, acyltransferases build and remodel complex lipids such as glycerolipids, glycerophospholipids, sphingolipids, waxes, and cholesterol esters. Notable examples include acyl-CoA:cholesterol acyltransferase (ACAT), which forms cholesterol esters for storage; glycerol-3-phosphate acyltransferases (GPATs), which initiate glycerolipid synthesis; 1-acylglycerol-3-phosphate acyltransferases (LPAAT) that generate phosphatidic acid; and diacylglycerol acyltransferases (DGAT) that complete triacylglycerol formation. In plants and microorganisms, additional acyltransferases participate in seed oil production, wax biosynthesis, and membrane lipid remodeling. There are multiple isoforms with varying substrate specificities and tissue distribution; many are membrane-associated enzymes with active sites oriented toward the cytosol or within the lipid bilayer.

Physiological roles of acyltransferases include energy storage, membrane lipid synthesis and remodeling, and specialized lipid production important for barriers such as skin and seed coats. Disruption or dysregulation of acyltransferase activity can affect lipid homeostasis and is studied in contexts ranging from metabolic diseases to agricultural trait engineering.