Lecithin: cholesterol acyltransferase (LCAT) is the plasma enzyme responsible for most HDL cholesteryl esters in human plasma. In species with cholesteryl ester transfer protein (CETP) it is also responsible for a significant proportion of VLDL and LDL cholesteryl esters. LCAT, through the esterification of cholesterol, plays a role in the reverse cholesterol transport pathway by facilitating the net movement of cholesterol from peripheral tissues back to the liver for excretion. LCAT deficiency results in low levels of plasma HDL, whereas a transgenic overexpression of LCAT results in increased plasma HDL concentrations.