Thermodynamic properties of acyl chain and mesophase transitions for phospholipids in KSCN

Abstract

The presence of a one molar solution containing KSCN was shown to induce an interdigitated gel phase in dipalmitoylphosphatidylcholine which can be deduced by examining the lipid thermodynamic phase transition parameters. Specifically, the sub- and pre-transitions can no longer be observed even by low resolution calorimetry. The main transition was completely reversible, however, with scan repetition. We concluded that the presence of 1 M KSCN induces an interdigitated bilayr phase in saturated chain phosphatidylcholines but not saturated chain phosphatidylethanolamines. The lamellar to non-lamellar phase transition was also examined in dielaideoylphosphatidylethanolamines. The presence of 1 M KSCN raised the Lα to H11 phase transition temperature indicating that the lamellar phase has been stabilized. The presence of KSCN thus affects the packing within the bilayer such that it is the ‘preferred’ thermodynamic phase.