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Over 40 years of development, PEGylation technology is now widely used for the modification of proteins, peptides, antibody fragments, oligonucleotides, and small molecules, as putative New Molecule Entities (pNMEs).  Among the advantages of PEGylation technology are the following:

       Increased solubility and stability;

       Decreased immunogenicity and toxic profile;

       Optimized pharmacokinetics leading to increased blood circulation of the drug and systemic drug exposure, as well as increased bioavailability for small molecules;

       Increased in vivo efficacy and clinical effectiveness;

       Decreased frequency of administration leading to high patient compliance

PEGs conjugate of protein drugs are usually prepared by techniques that employ random derivatization of lysine residues (1st generation PEGylation technology).  Although most of PEGylated drugs currently on market were developed by using this method, the overall utility of these methods are limited, due to the heterogeneity and decreased bioactivity of the products.  Even after extensive optimization, the reactions between activated PEG and free amino groups commonly result in multiple PEGylated isoforms with non-uniform chemical and pharmaceutical properties.  Therefore, the development of methods for the site-specific PEGylation of proteins is essential for developing more useful and safer protein drugs.

PegBio has developed proprietary and new generations of PEGylation technologies that include:

Site specific PEGylation (2nd generation of PEGylation)N-terminal specific PEGylation

1. N-terminal specific PEGylation

PegBio has developed N-terminal specific PEGylation by conjugating reactive PEG derivatives to proteins under certain conditions. N-Hydroxysuccinimide or propionaldehyde PEG derivatives were conjugated to proteins, leading to the selective or at least preferential N-terminal PEGylation of the protein.

2. The thiol-selective PEGylation

PEGylation of cysteine residues present in the protein or alternatively introduced into the protein by site-directed mutagenesis, we have employed either maleimide- or haloacetate-based PEG derivatives. The approach has been designed to enable peptides and recombinant proteins to improved pharmacokinetic properties.  As the surface area peptide is much smaller than larger biologics, the 1st generation PEGylation approaches can’t be applied, PegBio scientists have combined peptide re-engineered/mutagenesis approach and the site-specific PEGylation technology to optimize the bioactivity of an anti-diabetic peptide, resulting in substantially improved plasma half-life without reducing its bioactivity.

Enzymatic PEGylation (3rd generation of PEGylation)

PegBio has also developed a new generation of PEGylation technology, in which an enzymatic method is used for the covalent binding of PEG moieties to pharmaceutical proteins.  In this technology, we use transglutaminase (TGase) to attack preferentially or selectively only one or few specific amino acids on the proteins, enabling us to develop next-generation of biopharmaceuticals.

PegBio offers all kinds of PEGylation service to universities, research institutes, and pharmaceutical companies based on our above proprietary PEGylation platforms.  Please contact us for more details.

The following are figures of HPLC (ELSD) and SDS-PAGE analyses of PEGylated peptides.

HPLC-ELSD analysis of PEGylated peptides


Peptide 4 kDa

mPEG 30 kDa

 mPEG-peptide 34 kDa
SDS-PAGE analysis of PEGylated peptides


1) Marker; 2) mPEG20000-peptide; 3) mPEG30000-peptide; 4) mPEG40000-peptide; 5) mPEG20000*2-peptide.


PegBio Co., Ltd.  Tel.: 86-512-6295-6128; Fax: 86-512-6295-6130
Address: BioBay Building A3 (Suite 418), 218 Xinghu Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China