cholesteryl

Cholesteryl is a term used to denote derivatives of cholesterol in which the hydroxyl group is esterified with fatty acids. The most common form is cholesteryl esters, where cholesterol is linked by an ester bond to a fatty acid. These compounds are hydrophobic and form the core lipids of many lipoprotein particles.

Cholesteryl esters are central to cholesterol transport and storage. In plasma, lecithin–cholesterol acyltransferase (LCAT) on high-density lipoprotein (HDL) converts free cholesterol to cholesteryl esters, which pack into the particle core and drive maturation of HDL. In cells, acyl-CoA:cholesterol acyltransferase (ACAT, also known as SOAT) enzymes convert free cholesterol to cholesteryl esters for storage in cytosolic lipid droplets; ACAT1 is widespread, ACAT2 is enriched in liver and intestine. Free cholesterol released by lipolysis can be re-esterified and stored or exported in lipoproteins via cholesterol efflux.

Cholesteryl esters are hydrolyzed by cholesteryl ester hydrolases when cholesterol is needed by membranes or steroidogenic tissues. Abnormal accumulation of cholesteryl esters in macrophages contributes to foam cell formation and atherosclerotic plaque development.

Common cholesteryl esters include cholesteryl palmitate and cholesteryl oleate, formed with palmitic and oleic acids, respectively.