Which enzyme releases free cholesterol from macrophages?

• A. Cholesterol Ester Hydrolase
• B. Hormone-Sensitive Lipase
• C. Lipoprotein Lipase
• D. Lecithin-Cholesterol Acyltransferase

Answer: (A)

Releasing free cholesterol from macrophages involves breaking down stored cholesteryl esters. The enzyme that does this in macrophages is cholesterol ester hydrolase, which cleaves the ester bond to yield free cholesterol and fatty acids. This free cholesterol can then be moved out of the macrophage for transport to the liver, often via ABCA1 to HDL as part of reverse cholesterol transport. In contrast, Lecithin-cholesterol acyltransferase acts on free cholesterol to form cholesterol esters on HDL—not on macrophage stores—so it doesn’t release cholesterol from macrophages. Lipoprotein lipase and hormone-sensitive lipase act mainly on triglycerides (and, in some contexts, cholesteryl esters) but are not the primary enzymes responsible for freeing cholesterol from macrophage stores.