Interactions of lipid vesicles with solvent in heavy and light water
The phase-transition properties of lipid vesicles prepared from 1,2-distearoyl-, 1,2-dipalmitoyl-, and 1,2-dimyristoyl-L-3-glycerylphosphatidylcholines in D/sub 2/O and H/sub 2/O were compared. The phase-transition temperatures were 0.2 to 0.4/sup 0/C higher in D/sub 2/O than in H/sub 2/O. In general, the D/sub 2/O solvent effect caused increases in the enthalpy (..delta..H), entropy (..delta..S), and free energy (..delta..G) of the melting, with the enhancement ranging from 230 to 1170 cal/mol, from 0.7 to 2.0 eu, and from 4 to 12 cal/mol respectively. These observations are consistent with the premises that water is present around the hydrocarbon tails of lipid vesicles, and the melting of the difference in the amount of the more structured water around the tails in gel and liquid-crystalline phases is a major contribution to ..delta..H. Some recent findings regarding the phase-transition properties of mixed-chain and fluoro-substituted phosphatidylcholines are also consistent with this mechanism. 1 figure, 3 tables.
- Research Organization:
- New York State Dept. of Health, Albany
- OSTI ID:
- 6447466
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 86:18; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
400302* -- Organic Chemistry-- Isotope Effects-- (-1987)
COMPARATIVE EVALUATIONS
DATA
DEUTERIUM
DEUTERIUM COMPOUNDS
DISPERSIONS
ENERGY
ENTHALPY
ENTROPY
EXPERIMENTAL DATA
FREE ENTHALPY
HEAVY WATER
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INFORMATION
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
LIPIDS
MEDIUM TEMPERATURE
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
STABLE ISOTOPES
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
WATER