Cholesterol esters are a dietary lipid, which derived from cholesterol. Cholesterol esters are formed when the body produces enzymes to produce a metabolic reaction with the cholesterol itself. The ester bond is formed between the carboxylate group of a fatty acid and the hydroxyl group of cholesterol. cholesterol ester lipidomics.creative-proteomics.com/cholesterol-ester-targeted-lipidomics.htm