Dependence on phospholipid composition of the fraction of cholesterol undergoing spontaneous exchange between small unilamellar vesicles

Journal Article · Tue Aug 25 04:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00391a037· OSTI ID:5998317

Bar, L K; Barenholz, Y; Thompson, T E

Spontaneous cholesterol exchange between small unilamellar vesicles comprised of different phospholipids and their binary mixtures has been studied in order to understand the factors involved in the establishment and maintenance of intracellular cholesterol distributions. Exchange was performed from neutral donor vesicles containing different cholesterol concentrations, traces of (/sup 3/H)cholesterol, and (/sup 14/C)cholesteryl oleate as a nonexchangeable marker. The acceptor vesicles, in 10-fold excess, had the same composition, 15 mol % phosphatidylglycerol was included to permit chromatographic separation. Data were best fitted by a single exponential and a base value. In donor vesicles containing only one phospholipid, the kinetic rate constants agreed with data reported previously; however, the base values were larger than the expected equilibrium value of 9.09%. The size of this nonexchangeable pool and the exchange rate were found to depend on the type of phospholipid. In binary phospholipid donor systems, well above the transition temperatures of lipid components, the exchange parameters were preferentially closer to those of one component according to the order POPC > DMPC > DPPC > bovine brain SPM.

• Research Organization: Univ. of Virginia School of Medicine, Charlottesville
• OSTI ID: 5998317
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:17; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CHEMICAL COMPOSITION
CHOLESTEROL
CHROMATOGRAPHY
ESTERS
HYDROXY COMPOUNDS
ISOTOPE RATIO
LABELLED COMPOUNDS
LIPIDS
MEMBRANE TRANSPORT
MONOCARBOXYLIC ACIDS
OLEIC ACID
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHOLIPIDS
SEPARATION PROCESSES
STEROIDS
STEROLS
THIN-LAYER CHROMATOGRAPHY
TRITIUM COMPOUNDS