Back to Search
Start Over
Thermotropic behavior of galactosylceramides with cis-monoenoic fatty acyl chains
- Source :
- Biochimica et Biophysica Acta (BBA) - Biomembranes. 1372:347-358
- Publication Year :
- 1998
- Publisher :
- Elsevier BV, 1998.
-
Abstract
- To define the thermotropic behavior of galactosylceramides (GalCer) containing cis monounsaturated acyl chains, N-X:1Delta(X-9) cis galactosylsphingosines (GalSph) were synthesized (where X=24, 22, 20, or 18) and investigated by differential scanning calorimetry (DSC). After hydration of dried glycolipid, aqueous dispersions were prepared by repetitive heating and freeze-thaw cycles. The DSC data clearly showed that introducing a single cis double bond into the acyl chain of GalCer lowers the transition temperature of the main endothermic peak and affects the kinetics of formation of various metastable and stable gel phases. More importantly, the data emphasize the role that double bond location in concert with acyl chain length play in modulating the thermotropic behavior of GalCers. In contrast to the 18:1 GalCer and 20:1 GalCer endotherms which remain unchanged after identical repetitive heating scans and low temperature incubations, the thermotropic responses of 22:1 GalCer and 24:1 GalCer depended directly upon incubation time at lower temperatures following a heating scan. Only after extended incubation (4-5 days) did the endotherms revert to behavior observed during the initial heating scan that followed sample preparation by cyclic heating and freeze-thaw methods. The extended incubation times required for 22:1 GalCer and 24:1 GalCer to assume their more stable packing motifs appear to be consistent with nucleation events that promote transbilayer interdigitation. Yet, due to the slow kinetics of the process, the presence of cis monounsaturation in very long acyl chains that are common to GalCer may effectively inhibit transbilayer lipid interdigitation under physiological conditions.
- Subjects :
- chemistry.chemical_classification
Hot Temperature
Calorimetry, Differential Scanning
Double bond
Chemistry
Stereochemistry
Galactosylceramides
Fatty Acids
Kinetics
Psychosine
Biophysics
Nucleation
chemical and pharmacologic phenomena
Cell Biology
Calorimetry
Biochemistry
Thermotropic crystal
Article
carbohydrates (lipids)
Differential scanning calorimetry
Glycolipid
Thermodynamics
lipids (amino acids, peptides, and proteins)
Subjects
Details
- ISSN :
- 00052736
- Volume :
- 1372
- Database :
- OpenAIRE
- Journal :
- Biochimica et Biophysica Acta (BBA) - Biomembranes
- Accession number :
- edsair.doi.dedup.....ff9c22ffe4ee04cf47a03dffd724bbf9