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Modifying a peptide to include polyethylene glycol (PEG) groups may improve solubility and bioavailability. Protein PEGylation can protect the protein from proteolytic degradation and increase its half-life in biological applications, decrease its antigenisity or potential toxicity, improve its solubility and decrease aggregation.

Applications of PEGylated Peptides and Proteins

PEGylation can increase the half-life of peptides and proteins in biological applications by protecting them from proteolytic digestion (Thi-Nguyen, NT, et al, J.Biotech. 2019, 306, 89-96; Fischer, C.; et al. Eur. J. Med. Chem. 2019, 166, 119-124; Niida, A, et al. Bioorg. Med. Chem. 2018, 26, 566-572.). In addition, PEGylation can mask the peptide or protein so that it does not produce an immune response (da-Silva-Freitas, D. et al. Protein Pept. Lett. 2015, 22, 1133-1139). Thus many PEGylated peptides and proteins are being examined as potential drugs and drug candidates.

PEGylated peptides also have potential uses as special coatings for materials utilized in biological applications. Peptide-PEG amphiphiles have been used to produce a cytophobic coating. The coating greatly reduced adhesion of mammalian cells and significantly reduced biofilm formation by S. aureus.(Kenan, DJ. et al. Chem. Biol. 2006, 13, 695-700).

Fmoc-PEG Linkers and PEGylation Reagents

Fmoc-Amino-PEG-Propionic Acids

Amino-PEG-propionic acid linkers have a protected amine at one end and are attached to a three-carbon acid at the other. They are useful for linking peptides and proteins to tags or for linking peptides to other biomolecules. These PEG linkers are available in the largest selection of lengths and protecting groups.

Fmoc-Amino-PEG-Acetic Acids

The applications of these PEG linkers are similar to the amino-PEG-propionic acid linkers, but with greater stability under basic conditions.


This PEG spacer is useful for linking peptides and proteins through acid groups either at the C-terminus or at Asp or Glu side chains.


Methyl-PEG-amines are used to modify peptides and proteins with PEG at acid groups such as the C-terminus or Asp or Glu side chains.


These PEGylating reagents are used to attach PEG to peptides and proteins on the N-terminus and Lys side chains.


This PEGylated reagent is used to attach PEG to peptides and proteins through Cys side chains.

The PEGylation reagents available from AAPPTec are homogeneous compounds having defined molecular weights and discrete chain lengths. They provide consistent performance in peptide and protein modification applications. In contrast, typical PEG reagents are heterogeneous mixtures containing a range of molecular weights and chain lengths.

From Fmoc-PEG linkers to PEG based reagents for modifying acids, amines and thiols, AAPPTec has the PEG products to enhance peptide and protein properties at affordable prices. AAPPTec’s Fmoc-PEG linkers and reagents are priced significantly below our competitors’ worldwide but with equal or superior purity and quality.