The covalent attachment of polyethylene glycol (PEG) to commonly used protecting groups and their use in peptide synthesis was examined. PEG bound to fluorenyl- and benzyl- type side chain protection for Lys and Glu results in increased solubility of hydrophobic peptides due to a distruption of beta-sheet conformations. PEG-protected peptides can be subject to HPLC purification and further used in convergent strategies for the synthesis of large peptides.