Coexistence of immiscible mixtures of palmitoylsphingomyelin and palmitoylceramide in monolayers and bilayers

JON V. BUSTO; MARÍA LAURA FANANI; LUISINA DE TULLIO; JESÚS SOT; BRUNO MAGGIO; FÉLIX M. GOÑI; ALICIA ALONSO

Biophys. J.

Biophysical Society

Año: 2009 vol. 97 p. 2717 - 2717

0006-3495

p>A combination of lipid monolayer- and bilayer-based model systems has been applied to explore in detail the interactions between and organization of palmitoylsphingomyelin (pSM) and the related lipid palmitoylceramide (pCer). Langmuir balance measurements of the binary mixture reveal favorable interactions between the lipid molecules. A thermodynamically stable point is observed in the range ~30?40 mol % pCer. The pSM monolayer undergoes hyperpolarization and condensation with small concentrations of pCer, narrowing the liquid-expanded (LE) to liquid-condensed (LC) pSM main phase transition by inducing intermolecular interactions and chain ordering. Beyond this point, the phase diagram no longer reveals the presence of the pSM-enriched phase. Differential scanning calori