Incorporating a Monofluoroalkene into the Backbones of Short Peptides: Evaluating the Impact on Local Hydrophobicity

The local hydrophobicity of an amino acid residue in a peptide sequence can be determined by measuring the hydrophobicity index (φ₀ ) by reversed-phase (RP) HPLC. Herein, the impact on the local hydrophobicity of the replacement of an amide by a monofluoroalkene unit in short peptides is discussed. Monofluoroalkene-containing dipeptides and tripeptides were synthesized, as well as their natural parent compounds, and the hydrophobicity indexes of these short peptides and peptidomimetics were determined. Comparison between the natural parent peptides and their alkene-containing analogues was made, and the dependence of the peptidomimetic analogues' behaviour on the pH and the solvent was studied. It was found that the presence of a monofluoroalkene unit enhanced a peptide's hydrophobicity.