Remodelling of reconstituted high density lipoproteins by lecithin: cholesterol acyltransferase
Discoidal reconstituted high density lipoproteins (rHDL) with a diameter of 7.9 nm, a molar ratio of egg phosphatidylcholine (PC): unesterified cholesterol (UC): cholesteryl esters (CE): apolipoprotein (apo) A-I of 33:7:0:1 and containing two molecules of apoA-1 per particle were incubated with leci...
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doaj-ff9c9f6da2634a2d8c675683e9c453ed2021-04-26T05:48:47ZengElsevierJournal of Lipid Research0022-22751996-09-0137919621970Remodelling of reconstituted high density lipoproteins by lecithin: cholesterol acyltransferaseH Q Liang0K A Rye1P J Barter2Lipid Research Laboratory, Hanson Centre for Cancer Research, Adelaide, Australia.Lipid Research Laboratory, Hanson Centre for Cancer Research, Adelaide, Australia.Lipid Research Laboratory, Hanson Centre for Cancer Research, Adelaide, Australia.Discoidal reconstituted high density lipoproteins (rHDL) with a diameter of 7.9 nm, a molar ratio of egg phosphatidylcholine (PC): unesterified cholesterol (UC): cholesteryl esters (CE): apolipoprotein (apo) A-I of 33:7:0:1 and containing two molecules of apoA-1 per particle were incubated with lecithin:cholesterol acyltransferase (LCAT) in the presence of low density lipoproteins as a source of additional UC and PC for the LCAT reaction. After 24 h of incubation, the rHDL had a diameter of 8.8 nm, a molar ratio of PC:UC:CE:apoA-I of 16:3:23:1 and contained three rather than two molecules of apoA-I per particle. The fact that there was no change in the concentration of rHDL-associated apoA-I indicated that the increase from two to three molecules of apoA-I per particle was achieved at the expense of a one-third reduction in the number of rHDL particles in a process that must have involved particle fusion. When the incubations were repeated in the presence of exogenous, lipid-free apoA-I, the resulting rHDL were identical in size and composition to those generated in its absence. Under these conditions, however, the increase from two to three molecules of apoA-I per rHDL particle coincided with a 50% increase in the concentration of rHDL-associated apoA-I. Thus, when lipid-free apoA-I is available, the LCAT-mediated increase in number of apoA-I molecules per rHDL particle is achieved by a direct incorporation of lipid-free apolipoprotein without any need for particle fusion and therefore without a reduction in the number of rHDL particles.http://www.sciencedirect.com/science/article/pii/S0022227520375611 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
H Q Liang K A Rye P J Barter |
spellingShingle |
H Q Liang K A Rye P J Barter Remodelling of reconstituted high density lipoproteins by lecithin: cholesterol acyltransferase Journal of Lipid Research |
author_facet |
H Q Liang K A Rye P J Barter |
author_sort |
H Q Liang |
title |
Remodelling of reconstituted high density lipoproteins by lecithin: cholesterol acyltransferase |
title_short |
Remodelling of reconstituted high density lipoproteins by lecithin: cholesterol acyltransferase |
title_full |
Remodelling of reconstituted high density lipoproteins by lecithin: cholesterol acyltransferase |
title_fullStr |
Remodelling of reconstituted high density lipoproteins by lecithin: cholesterol acyltransferase |
title_full_unstemmed |
Remodelling of reconstituted high density lipoproteins by lecithin: cholesterol acyltransferase |
title_sort |
remodelling of reconstituted high density lipoproteins by lecithin: cholesterol acyltransferase |
publisher |
Elsevier |
series |
Journal of Lipid Research |
issn |
0022-2275 |
publishDate |
1996-09-01 |
description |
Discoidal reconstituted high density lipoproteins (rHDL) with a diameter of 7.9 nm, a molar ratio of egg phosphatidylcholine (PC): unesterified cholesterol (UC): cholesteryl esters (CE): apolipoprotein (apo) A-I of 33:7:0:1 and containing two molecules of apoA-1 per particle were incubated with lecithin:cholesterol acyltransferase (LCAT) in the presence of low density lipoproteins as a source of additional UC and PC for the LCAT reaction. After 24 h of incubation, the rHDL had a diameter of 8.8 nm, a molar ratio of PC:UC:CE:apoA-I of 16:3:23:1 and contained three rather than two molecules of apoA-I per particle. The fact that there was no change in the concentration of rHDL-associated apoA-I indicated that the increase from two to three molecules of apoA-I per particle was achieved at the expense of a one-third reduction in the number of rHDL particles in a process that must have involved particle fusion. When the incubations were repeated in the presence of exogenous, lipid-free apoA-I, the resulting rHDL were identical in size and composition to those generated in its absence. Under these conditions, however, the increase from two to three molecules of apoA-I per rHDL particle coincided with a 50% increase in the concentration of rHDL-associated apoA-I. Thus, when lipid-free apoA-I is available, the LCAT-mediated increase in number of apoA-I molecules per rHDL particle is achieved by a direct incorporation of lipid-free apolipoprotein without any need for particle fusion and therefore without a reduction in the number of rHDL particles. |
url |
http://www.sciencedirect.com/science/article/pii/S0022227520375611 |
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