The effect of N-acyl ethanolamines on phosphatidylethanolamine phase transitions studied by laurdan generalised polarisation
✍ Scribed by Annarina Ambrosini; Enrico Bertoli; Fabio Tanfani; Michal Wozniak; Giovanna Zolese
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 595 KB
- Volume
- 72
- Category
- Article
- ISSN
- 0009-3084
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✦ Synopsis
The effect of N-lauroylethanolamine (N-LEA) and N-oleoylethanolamine (N-OEA) on the thermal behaviour of fully hydrated egg phosphatidylethanolamine (TPE) was investigated by the steady-state fluorescence of 2dimethylamino-(6-1auroyl)-naphtalene (laurdan) and 1-(4-trimethylaminophenyl)-6-phenyl-l,3,5-hexatriene (TMA-DPH). The parameter generalised polarisation (GP), calculated by exciting laurdan at 340 and 410 nm, revealed the gel to liquid crystalline lamellar (Let) as well as the Let to inverse hexagonal (HII) phase transitions of TPE. The Let to Hit phase transition was not detected in TPE/N-OEA system, probably because of the formation of an intermediate Q224 cubic phase. The formation of Q224 phase in TPE/N-OEA and TPE/N-LEA systems was previously demonstrated by X-ray diffraction, but neither laurdan generalised polarisation nor TMA-DPH steady-state fluorescence anisotropy measurements revealed the presence of this phase. It is suggested that the lack of detection of the cubic phase is probably due to the similarity in dynamic characteristics and hydration levels of phospholipid headgroups in the bilayer and cubic phases.