Solution Phase Synthesis and Conformational Analysis of Glu-Ser-Leu-Ser-Ser-Ser-Glu-Glu-NHMe and Its Peptide Congeners (Non-Phosphorylated Region 14-21 of Bovine β-Casein A₂)

Abstract

The octapeptide H-Glu-Ser-Leu-Ser-Ser-Ser-Glu-Glu-NHMe.CF₃CO₂H and its five shorter peptide congeners (from tripeptide to heptapeptide ) were prepared in high yield and purity by the Boc mode of solution phase peptide synthesis followed by palladium- catalysed hydrogenolytic deprotection of the six protected peptides in 50% CF₃CO₂H/CH₃CO₂H solution. The analysis of the six peptides by ¹³C n.m.r. spectroscopy and C₁₈ reversed-phase chromatography suggested that a structural arrangement commenced at the hexapeptide stage and was considered to be due to the formation of a β-turn conformation.