Poly(ethylene glycol) (PEG) has been widely used to prolong the residence time of proteins in blood and to decrease their immunogenicity and antigenicity. A drawback of this polymer lies in its polydispersity that makes difficult the identification of the sites of protein modification. This is a mandatory requirement if a PEGylated protein should be approved as a drug. Here, a fast and reliable method is proposed to characterize proteins conjugated at the level of glutamine (Gln) residues using microbial transglutaminase (TGase). The novelty resides in the use of a monodisperse Boc-PEG-NH(2) for the derivatization that allows the direct identification of the sites of PEGylation by electrospray ionization mass spectrometry (ESI-MS). The procedure has been tested on three model proteins, namely, human granulocyte colony-stimulating factor, human growth hormone, and horse heart apomyoglobin. The Gln residues linked to the polymer chain were easily identified by ESI-MS and tandem MS analyses, demonstrating the advantage of using a monodisperse polymer in combination with mass spectrometry for an easy characterization of conjugated proteins. Interestingly, the PEGylation reaction led to the production only of mono- and bis-derivative products, indicating that the TGase-mediated PEGylation can be extremely selective and thus very useful for the derivatization of protein drugs.
Titolo: | Transglutaminase-mediated PEGylation of proteins: direct identification of the sites of protein modification by mass spectrometry using a novel monodisperse PEG |
Autori: | |
Data di pubblicazione: | 2009 |
Rivista: | |
Abstract: | Poly(ethylene glycol) (PEG) has been widely used to prolong the residence time of proteins in blood and to decrease their immunogenicity and antigenicity. A drawback of this polymer lies in its polydispersity that makes difficult the identification of the sites of protein modification. This is a mandatory requirement if a PEGylated protein should be approved as a drug. Here, a fast and reliable method is proposed to characterize proteins conjugated at the level of glutamine (Gln) residues using microbial transglutaminase (TGase). The novelty resides in the use of a monodisperse Boc-PEG-NH(2) for the derivatization that allows the direct identification of the sites of PEGylation by electrospray ionization mass spectrometry (ESI-MS). The procedure has been tested on three model proteins, namely, human granulocyte colony-stimulating factor, human growth hormone, and horse heart apomyoglobin. The Gln residues linked to the polymer chain were easily identified by ESI-MS and tandem MS analyses, demonstrating the advantage of using a monodisperse polymer in combination with mass spectrometry for an easy characterization of conjugated proteins. Interestingly, the PEGylation reaction led to the production only of mono- and bis-derivative products, indicating that the TGase-mediated PEGylation can be extremely selective and thus very useful for the derivatization of protein drugs. |
Handle: | http://hdl.handle.net/11577/2452688 |
Appare nelle tipologie: | 01.01 - Articolo in rivista |