Effect of Lecithin on the Esterification of Lipoprotein Cholesterol by Lecithin-Cholesterol Acyltransferase

The initial rate of the lecithin-cholesterol acyltransferase reaction in human plasma was enhanced by the addition of lecithin dispersions, especially in the presence of apo A-I. To clarify the nature of this enhancement, purified enzyme and isolated human plasma lipoproteins were used. Without added lecithin the enzyme did not efficiently utilize the cholesterol of all lipoproteins; very low density lipoproteins (VLDL), low density lipoproteins (LDL), and high density lipoproteins (HDL). However, the preincubation of lipoproteins with egg lecithin and apo A-I enhanced the cholesterol esterification. At a constant level of lipoprotein cholesterol, the esterification of LDL and VLDL cholesterol was enhanced to a greater extent at lower lecithin levels than HDL. Although the esterification of HDL cholesterol was enhanced by the addition of lecithin alone, the presence of both lecithin and apo A-I further increased the cholesterol esterification rate at higher lecithin levels. When a constant level of apo A-I was included in the plasma and the model systems, a decrease in cholesterol esterification was observed at high lecithin levels. This decrease in esterification rate was overcome by adding apo A-I in increasing amounts. The level of apo A-I required for the maximum esterification of lipoprotein cholesterol was dependent on the amount of lecithin added.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Food Science

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Wiessner, John Henry

• Chemistry, Biochemistry

Language dc:language

eng

Identifier

(UMI)AAI8026620

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F66977