LCAT Activity (Lecithin-Cholesterol Acyltransferase)
Biological or Clinical Significance:
Lecithin-cholesterol acyltransferase (LCAT) is a 63kDa glycoprotein synthesized in the liver, released into the circulation, and primarily activated by apo A-I. LCAT is an enzyme that catalyzes the formation of cholesteryl esters on HDL, particularly HDL3, and by that promotes maturation of HDL particles in plasma and facilitates reverse cholesterol transport by maintaining a concentration gradient for the diffusion of cellular unestrified cholesterol to HDL. LCAT transfers fatty acid from the second carbon position of phosphatidylcholine (lecithin) to the 3 beta-OH group of free cholesterol forming lysophosphatidylcholine and a cholesteryl ester. Cholesterol estrification by LCAT may play a significant role in the prevention of cardiovascular disease, improving cholesterol exportation in biliary acids. Measurement of LCAT activity is potentially useful in clarifying the aspects of lipid metabolism related to reverse cholesterol transport.
Principle of Test Method:
The LCAT assay is an automated enzymic method with sample pretreatment.