title: A study of the conformational equilibrium of DL-oligophenylalanines in nonpolar solvents in the presence and absence of lipids by high-performance liquid chromatography.
abstract: The usefulness of high-performance size-exclusion liquid chromatography (HPSEC) for the separation of dimeric and monomeric species of DL-alternating oligophenylalanines is demonstrated for the first time. The experimental data obtained as a function of time fit a simple dimer-monomer equilibrium in a nonpolar solvent such as tetrahydrofuran. A higher extent of monomerization and a decrease in the time required for reaching equilibrium were detected in the presence of either water or phosphatidylcholine. The analysis of the relative proportions of the two separated species under equilibrium conditions has allowed the influence of the oligopeptide chain length on the stability of dimeric species to be determined. The advantages of this methodology, in combination with spectroscopic techniques, in studies on autoassociating peptides are considered.
authors.affiliation: Departament de Bioquímica i Biología Molecular, Facultad de Ciencias, Universitat de Valencia, Spain.
authors.forename: M C
authors.initials: MC
authors.lastname: Baño
authors.forename: L
authors.initials: L
authors.lastname: Braco
authors.forename: B
authors.initials: B
authors.lastname: Celda
authors.forename: C
authors.initials: C
authors.lastname: Abad
mesh_terms: D002851:Chromatography, High Pressure Liquid; D009842:Oligopeptides; D010649:Phenylalanine / Q000031:analogs & derivatives*; D010713:Phosphatidylcholines; D011487:Protein Conformation; D012997:Solvents
chemical_list: D009842:Oligopeptides; D010713:Phosphatidylcholines; D012997:Solvents; D010649:Phenylalanine