Conformational Studies of Synthetic Polyethylene Glycol Bound Substance P and its Lower Analogues

The synthesis o f Substance P (SP) bound at the C-terminal methionine to polyethylene glycol monomethyl ether (M -PEG ) is described. SP-PEG-M is obtained in good yield by the liquidphase peptide synthesis. Gel permeation chromatography reveals that aggregated forms of the PEG-bound peptides are absent in CHC13. CD and IR spectra point to a /3-turn located at the Nterminal part o f SP-PEG-M . In binding studies and in vivo assays the described compounds are devoid of biological activity.