Effect of γ-Oryzanol on the LE-LC Phase Coexistence Region of DPPC Langmuir Monolayer.
J Membr Biol
; 256(4-6): 413-422, 2023 Dec.
Article
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| MEDLINE
| ID: mdl-37269365
We have studied the effect of relative composition of γ-Oryzanol (γ-Or) on the liquid expanded-liquid condensed phase coexistence region in the mixed Langmuir monolayer of γ-Or and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) molecules at air-water interface. The surface manometry studies at a fixed temperature show that the mixture of γ-Or and DPPC forms a stable monolayer at air-water interface. As the relative composition of γ-Or increases the range of area per molecule over which the coexistence of liquid expanded (LE)-liquid condensed (LC) phases exists reduces. Although the LE-LC phase coexistence corresponds to the first-order phase transition, the slope of the surface pressure-area per molecule isotherm is non-zero. Earlier studies have attributed the non-zero slope in LE-LC phase coexistence region to the influence of the strain between the ordered LC phase and disordered LE phase. The effect of strain on the coexistence of LE-LC phases can be studied in terms of molecular density-strain coupling. Our analysis of the liquid condensed-liquid expanded coexistence region in the isotherms of mixed monolayers of DPPC and γ-Or shows that with the increase in the mole fraction of sterol in the mixed monolayer the molecular lateral density-strain coupling increases. However, at 0.6 mole fraction of γ-Or in the mixed monolayer the coupling decreases. This is corroborated by the observation of minimum Gibb's free energy of the mixed monolayer at this relative composition of γ-Or indicating better packing of molecules.
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Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fenilpropionatos
Idioma:
En
Revista:
J Membr Biol
Año:
2023
Tipo del documento:
Article
País de afiliación:
India
Pais de publicación:
Estados Unidos