Acyltransferase

Acyltransferase (AT) catalyzes the transfer of an acyl moiety from acyl-coenzyme A (acyl-CoA) to an acceptor. Acyltransferases play important roles in the maintenance of homeostasis in the human body and have been linked to various diseases. The Acyltransferase family includes acyl-CoA:cholesterol AT (ACAT), diacylglycerol AT (DGAT), and monoacylglycerol AT (MGAT) for the metabolism of lipids.

ACAT (acyl-coenzyme A:cholesterol acyltransferase) is an intracellular enzyme that catalyzes the formation of cholesterol esters from cholesterol and fatty acyl-coenzyme A. In mammals, two isoenzymes, ACAT1 and ACAT2, encoded by two different genes, exist. ACATs play important roles in cellular cholesterol homeostasis in various tissues.

DGAT (acyl-CoA:diacylglycerol acyltransferase) is an integral membrane enzyme that catalyses the last step of triacylglycerol synthesis from diacylglycerol and acyl-CoA. DGAT activity resides mainly in two distinct membrane bound polypeptides, known as DGAT1 and DGAT2.

MGAT (acyl-CoA:monoacylglycerol acyltransferase) catalyzes the synthesis of diacylglycerol, the precursor of physiologically important lipids such as triacylglycerol and phospholipids. In the intestine, MGAT plays a major role in the absorption of dietary fat because resynthesis of triacylglycerol is required for the assembly of lipoproteins that transport absorbed fat to other tissues.