13 Synthesis of Peptide Bioconjugates

Bioconjugates play an important role in several fields of biomolecular and biomedicinal sciences. Protein/polypeptide-based conjugates with covalently attached epitope peptides are considered as potential synthetic vaccine candidates and/or target antigens in affinity-based bioassays. This chapter describes the synthesis of two- and three-component bioconjugates using water-soluble branched chain polymericpolypeptides with multiple amino and/or carboxyl groups as macromolecular partners and oligopeptides as epitopes with small molecular mass. The synthetic procedures outline three major strategies for the incorporation of multiple copies of uniformly oriented peptide epitopes. In the first example, chloroacetylated polypeptide is conjugated with SH-peptide to form a thioether linkage. Second, two independent oligopeptides are introduced into a macromolecule by amide and disulfide bonds, respectively. In the third example, a new procedure is reported for the formation of disulfide bridges by the use of Npys-modified polypeptide and SH-peptide.