title: Synthesis of a peptide emulsifier with an amphiphilic structure.
abstract: Three kinds of peptides (H, S, and R) with 16 amino acid residues were synthesized, and their secondary structure and emulsifying properties (emulsifying activity and oil-binding property) were investigated to clarify the effects of conformational amphiphilicity. The amino acid compositions of the three peptides were the same (8 Leu and 8 Glu residues) but their sequences were different. Circular dichroism analysis showed that peptide H contained an alpha-helix at pH 5.5 but took a random structure at pH 7.0. Peptide S also contained an alpha-helix at pH 5.5, while a beta-sheet structure was predominant at pH 7.0. Peptide R took mainly a random structure at both pH 5.5 and pH 7.0. The helical properties of peptide H and peptide S were different; the alpha-helix of peptide H was amphiphilic, while that of peptide S was not. Under conditions where peptide H formed an amphiphilic alpha-helix, both the emulsifying activity and oil-binding property of the peptide significantly increased. The emulsifying properties of peptide S, which formed an amphiphilic beta-sheet at pH 7.0, were also good at that pH. We conclude that a peptide with an amphiphilic alpha-helix or beta-sheet structure has better emulsifying properties, hence a good peptide emulsifier could be designed by incorporating such a structure.
authors.affiliation: National Food Research Institute, Ministry of Agriculture, Forestry, and Fisheries, Ibaraki, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Saito
authors.forename: M
authors.initials: M
authors.lastname: Ogasawara
authors.forename: K
authors.initials: K
authors.lastname: Chikuni
authors.forename: M
authors.initials: M
authors.lastname: Shimizu
mesh_terms: D000327:Adsorption; D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D005079:Excipients / Q000138:chemical synthesis* / Q000737:chemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D017433:Protein Structure, Secondary; D013499:Surface Properties
chemical_list: D005079:Excipients; D010455:Peptides