title: Studies of gramicidin S analogues having various ring sizes by reversed-phase high-performance liquid chromatography.
abstract: Many gramicidin S analogues containing six to fourteen amino acid residues were synthesized and their chromatographic behaviour was investigated using reversed-phase high-performance liquid chromatography. Cyclo(-Val-Leu-Orn-Leu-D-Phe-Pro-Val-Orn-Leu-D-Phe-Pro-) gave double peaks in the chromatogram, whereas the other peptides gave a single peak. The influences of the concentration of this peptide, column temperature and flow-rate on the chromatographic separation were examined. The isomeric conformers were separated from each of the double peaks and were in equilibrium with each other at low temperatures. These results suggested that the presence of the additional L-Leu residue preceding the Orn residue gives rise to moderate stabilization of their conformers.
authors.affiliation: Department of Chemistry, Faculty of Science, Toho University, Chiba, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tamaki
authors.forename: S
authors.initials: S
authors.lastname: Akabori
authors.forename: I
authors.initials: I
authors.lastname: Muramatsu
mesh_terms: D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D006096:Gramicidin / Q000737:chemistry*; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry*
chemical_list: D010456:Peptides, Cyclic; D006096:Gramicidin