Synthesis of Novel Linear Multivalent Peptide Ligands Based on the Tetrapeptide MSH(4)

Abstract

This thesis describes the synthesis of a novel multimeric peptide ligand targeted to the human melanocortin 4 receptor. The synthesis of the peptide was attempted both by solid phase peptide synthesis and by solution phase peptide synthesis, leading to the conclusion that the necessary C- and N- terminal substituents were much easier to install via the solution phase route. The bifunctional peptide was purified and then multimerized in both protected and active amino acid forms using the copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) reaction. The multimers were characterized using MS and UV-Vis spectroscopy. It was found that a large portion of the monomer cyclized under CuAAC conditions, though sufficient multimerization took place to form up to nonamers, as determined by mass spectrometry.