Question

How does LCAT (PCAT) form cholesteryl esters from free cholesterol in blood? What is the function of apo A-1?

a) By hydrolysis
b) By oxidation
c) By esterification
d) By phosphorylation

Answer 1

LCAT forms cholesteryl esters from free cholesterol in blood through esterification, and apo A-1 activates LCAT.

Step-by-step explanation:

LCAT (Lecithin-Cholesterol Acyltransferase) is an enzyme that plays a crucial role in the formation of cholesteryl esters from free cholesterol in blood. LCAT catalyzes the esterification of free cholesterol with a fatty acid, resulting in the formation of cholesteryl esters. These cholesteryl esters are then incorporated into high-density lipoproteins (HDL) for transport.

Apo A-1 is a protein component of HDL and is responsible for activating LCAT. Apo A-1 acts as a cofactor for LCAT, enhancing its esterification activity and facilitating the formation of cholesteryl esters from free cholesterol.