Abstract
Mixtures of sn-1 (d) and sn-3 (l) enantiomers of fully hydrated dipalmitoylphosphatidylcholine (DPPC) were studied with differential scanning calorimetry and freeze-fracture microscopy. The pretransition temperature of racemic mixtures of DPPC was 1.8 C° below that of either pure sn-1 or sn-3 enantiomers, which had similar pretransition temperatures. The main transition temperature of racemic mixtures was also depressed, but to a lesser extent, 0.8 C°. Freeze-fracture images of liposomes of sn-1, sn-3, and racemic mixtures of DPPC frozen from the Pβ′ phase showed well-defined ripples of wavelength 13 nm. Lipid stereoconfiguration had no effect on ripple wavelength, configuration or amplitude, or on the number and nature of surface defects.
Original language | English (US) |
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Pages (from-to) | 235-243 |
Number of pages | 9 |
Journal | BBA - Biomembranes |
Volume | 946 |
Issue number | 2 |
DOIs | |
State | Published - Dec 22 1988 |
Keywords
- Dipalmitoylphosphatidylcholine
- Liposome
- Membrane structure
- Ripple phase
- Stereo chemistry