Utilization of various sterols by lecithin-cholesterol acyltransferase as acyl acceptors

Abstract

Highly purified lecithin-cholesterol acyltransferase of human plasma was used to study the utilization of various sterols as the acyl acceptor. The esterification of sterols was facilitated by the presence of a 3beta-hydroxyl group and the trans configuration of the A/B rings, as was evident from the lack of acceptor activity of all 3 alpha-hydroxy sterols tested and coprostanol. Cholesterol analogs in which the side chain is modified, such as campesterol, beta-sitosterol, desmosterol and stigmasterol, were less effective than cholesterol as acyl acceptors. However, androstan-3 beta-ol, which completely lacks the side chain, was found to be more active than cholesterol. The transfer of the acyl group to all effective sterols required the presence of the cofactor peptide apolipoprotein A-I.