The catalytic mechanism of LCAT involves several steps:
Binding of the enzyme to the surface of HDL particles. Recognition and binding of phosphatidylcholine and free cholesterol as substrates. Transfer of a fatty acid from phosphatidylcholine to cholesterol, forming cholesteryl ester and lysophosphatidylcholine. Release of the products and regeneration of the active site for another catalytic cycle.
The efficiency and specificity of LCAT’s catalytic activity depend on its interaction with Apolipoprotein A-I (ApoA-I), which acts as a cofactor and stabilizes the enzyme.
