Phospholipid Substrate Specificity of Purified Human Plasma Lecithin: Cholesterol Acyltransferase

Abstract

The reactivity of purified lecithin: cholesterol acyltransferase with a series of phospholipid substrates, in the presence and absence of the specific cofactor apo Al from human high density lipoprotein, indicated that the enzyme was specific for substrates containing a basic nitrogen atom, and that reaction was increased by N-methylation. Cholesteryl ester production from all substrates was stimulated by apo Al. This cofactor may act by trapping the cholesteryl ester product of the reaction.

Key Words:

• Cholesterol
• cofactor
• high density lipoproteins
• lecithin
• cholesterol acyltransferase
• phospholipid