UTILIZATION OF VARIOUS STEROLS BY LECITHIN-CHOLESTEROL ACYLTRANSFERASE AS ACYL ACCEPTORS

Highly purified lecithin-cholesterol acyltransferase [EC 2.3.1.43] 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 3.beta.-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. Androstan-3.beta.-o1, which completely lacks the side-chain, was more active than cholesterol. The transfer of the acyl group to all effective sterols required the presence of the cofactor peptide apolipoprotein A-I.