Inhibitory effects of oxidized low-density lipoprotein on the activity of plasma lecithin: cholesterol acyltransferase.
Lecithin: cholesterol acyltransferase (LCAT) is an enzyme that is important in the cholesterol reverse-transport system by converting the surface cholesterol of high-density lipoprotein (HDL) to cholesterol ester inside HDL. We have investigated changes in plasma LCAT activity induced by oxidized low-density lipoprotein (ox-LDL). (i) LCAT activity was inhibited by the addition of even a small amount of ox-LDL, (ii) This inhibitory effect was dose-dependent and was related to the degree of oxidation of LDL, (iii) As this inhibitory effect was not prevented by antioxidants, it is suggested that it does not occur via oxidation of substrate HDL. These results suggest that cholesterol reverse-transport via HDL may be affected by ox-LDL and they are noteworthy in suggesting a new physiological function for ox-LDL.
Kamiyama
S
S
Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, Sendai, Japan.
Kim
H J
HJ
Furukawa
Y
Y
D000975:Antioxidants / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D010084:Oxidation-Reduction; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000037:antagonists & inhibitors* / Q000097:blood
D000975:Antioxidants; D004791:Enzyme Inhibitors; D008077:Lipoproteins, LDL; D007862:Phosphatidylcholine-Sterol O-Acyltransferase