Format

Send to

Choose Destination
Biochim Biophys Acta. 2011 Jul;1808(7):1806-10. doi: 10.1016/j.bbamem.2011.02.020. Epub 2011 Mar 4.

Thermodynamic invariants of gel to the liquid-crystal 1,2-diacylphosphatidylcholines transition.

Author information

1
Institute of Protein Research, Russian Academy of Sciences, Moscow Region, Russia. spot@vega.protres.ru

Abstract

The bilayer phase transitions from the ripple gel phase (P'(β)) to the liquid-crystal phase (L(α)) of a series of 1,2-diacylphosphatidylcholines containing a linear saturated acyl chain (C=14-19) have been studied by high-pressure scanning microcalorimetry. It has been shown that at ambient pressure, the transition temperature increases non-linearly depending on the acyl chain length. Pressure stabilizes the gel phase of lipids in a similar way; the pressure derivatives of the logarithm transition temperature as function of pressure are identical for all lipids. Based on the results obtained it has been concluded that the ratio γ of volume to enthalpy increments upon transitions in 1,2-diacylphosphatidylcholines is not dependent on the acyl chain length. When pressure grows, this ratio decreases drastically remaining identical for all lipids studied. Besides it has been demonstrated that increments of coefficients of thermal expansibility and isothermal compressibility are also rigidly bound to each other. Semi-empirical equations permitting to estimate volume parameters of the gel-to-liquid transition for 1,2-diacylphosphatidylcholines are given. The reasons for invariance of γ are discussed.

PMID:
21377445
DOI:
10.1016/j.bbamem.2011.02.020
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center