Poly(ethylene glycol)s grafted onto crosslinked polystyrenes. 2. Multidetachably anchored polymer systems for the synthesis of solubilized peptides

Abstract

Poly(ethylene glycol)s grated onto suitably functionalized, crosslinked polystyrenes were introduced as a new class of multidetachably immobilized hydrophilic macromolecular supports for the synthesis of peptides. This new polymeric carrier system facilitates both the homogeneous solvation of the reaction site and the insolubilization of the substrate, which are prerequisites for an efficient multistep synthesis using polymeric supports. In these support systems, a strongly solvated hydrophilic linear chain molecule, poly(ethylene glycol) (PEG), is attached to an insoluble, crosslinked polystyrene through suitable anchoring linkages. At the free chain end of this supported PEG, amino acid residues were stepwise incorporated following the standard synthetic methodology for peptides. A special feature of these new carriers is that the use of an orthogonal set of anchoring linkages to connect the polystyrene, PEG and the peptide provides access to the PEG-bound solubilized peptide or to the free peptide, as desired. The applications of these new polymeric supports are illustrated by the synthesis of thioredoxin partial sequences in the free and PEG-bound solubilized forms.