Surface thermodynamics study of monolayers formed with heteroacid phospholipids of biological interest.
The interaction of 1-palmitoy-2-oleoyl-sn-glycero-3-phosphocoline (POPC) and 1-palmitoy-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), two of the major components in biological membranes, were investigated using the monolayer technique at the air-water interface. The pressure-area isotherms indicate that both phospholipids are miscible through all range of compositions. POPE-POPC form stable mixtures, with a minimum for the Gibbs energy of mixing at X(POPC) = 0.4. A virial equation of state was fitted to the experimental values. Positive values found for the second virial coefficient indicate repulsion between POPC and POPE. The interaction parameter was evaluated which indicated that a corresponding decrease in the repulsion occurs when POPC molar fraction is low. This effect suggests the existence of hydrogen bonds between POPE and the water beneath the interface.
Domènech
Oscar
O
Departament de Química Física, Universitat de Barcelona, Centre de Bioelectrònica i Nanobiociència (CBEN), Parc Científic de Barcelona, Josep Samitier 1-5, E-08028 Barcelona, Spain.
Torrent-Burgués
Juan
J
Merino
Sandra
S
Sanz
Fausto
F
Montero
M Teresa
MT
Hernández-Borrell
Jordi
J
D000388:Air; D006860:Hydrogen Bonding; D008081:Liposomes / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D008081:Liposomes; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010743:Phospholipids; D014867:Water; C028694:1-palmitoyl-2-oleoylphosphatidylcholine