Effect of free cholesterol on incorporation of triolein in phospholipid bilayers

Journal Article · Tue Sep 08 04:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00392a036· OSTI ID:5932760

Spooner, P J.R.; Small, D M

Triacylglycerols are the major substrates for lipolytic enzymes that act at the surface of emulsion-like particles such as triglyceride-rich lipoproteins, chylomicrons, and intracellular lipid droplets. This study examines the effect of cholesterol on the solubility of a triacylglycerol, triolein, in phospholipid surfaces. Solubilities of (carbonyl-/sup 13/C) triolein in phospholipid bilayer vesicles containing between 0 and 50 mol % free cholesterol, prepared by cosonication, were measured by /sup 13/C NMR. The carbonyl resonances from bilayer-incorporated triglyceride were shifted downfield in the /sup 13/C NMR spectra from those corresponding to excess, nonincorporated material. This enabled solubilities to be determined directly from carbonyl peak intensities at most cholesterol concentration. The bilayer solubility of triolein was inversely proportional to the cholesterol/phospholipid mole ratio. In pure phospholipid vesicles the triolein solubility was 2.2 mol %. The triglyceride incorporation decreased to 1.1 mol % at a cholesterol/phospholipid mole ratio of 0.5, and at a mole ratio of 1.0 for the bilayer lipids, the triolein solubility was reduced to just 0.15 mol %. The effects of free cholesterol were more pronounced and progressive than observed previously on the bilayer solubility of cholestery oleate. As with cholesteryl oleate, they suggest that cholesterol also displaces solubilized triglyceride to deeper regions of the bilayer.

• Research Organization: Boston Univ. School of Medicine, MA
• OSTI ID: 5932760
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:18; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BIOCHEMISTRY
CARBON 13
CARBON ISOTOPES
CHEMISTRY
CHOLESTEROL
ELECTRON MICROSCOPY
ESTERS
EVEN-ODD NUCLEI
HYDROXY COMPOUNDS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
LIPIDS
MAGNETIC RESONANCE
MEMBRANES
MICROSCOPY
NUCLEAR MAGNETIC RESONANCE
NUCLEI
OILS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OTHER ORGANIC COMPOUNDS
PHOSPHOLIPIDS
RESONANCE
STABLE ISOTOPES
STEROIDS
STEROLS
TRIGLYCERIDES
TRIOLEIN
UPTAKE