To prepare long-circulating liposomes, poly(ethylene glycol) (PEG)-lipid is usually mixed with other lipid components before vesicle formation. PEG-lipids can also be postinserted in the outer layer of liposomes after the preparation. In this study, PEG-distearoylphosphatidylethanolamine was incorporated by postinsertion technique into liposome-encapsulated hemoglobin (LEH) carrying neutral or ...

PEGylation of antibodies is known to increase their half-life in systemic circulation, but nothing is known regarding whether PEGylation can improve the inhibitory potency of antibodies against target receptors. In this paper, we have examined this question using antibodies directed to Sialoadhesin (Sn), a macrophage-restricted adhesion molecule that mediates sialic acid dependent binding to di...

In this study, N-terminal site-specific mono-PEGylation of the recombinant lidamycin apoprotein (rLDP) of lidamycin (LDM) was prepared using a polyethyleneglycol (PEG) derivative (M w 20 kDa) through a reactive terminal aldehyde group under weak acidic conditions (pH 5.5). The biochemical properties of mPEG-rLDP-AE, an enediyne-integrated conjugate, were analyzed by SDS-PAGE, RP-HPLC, SEC-HPLC ...

PEGylation is an attractive strategy to enhance the therapeutic efficacy of proteins with a short serum half-life. It can be used to extend the serum persistence and to reduce the immunogenicity of proteins. However, PEGylation can also lead to a decrease in the functional activity of the molecule to which it is applied. We constructed site-specifically PEGylated variants of anti-p185(HER-2) an...

PEGylation is a successful approach to improve potency of a therapeutic protein. The improved therapeutic potency is mainly due to the steric shielding effect of PEG. However, the underlying mechanism of this effect on the protein is not well understood, especially on the protein interaction with its high molecular weight substrate or receptor. Here, experimental study and molecular dynamics si...

We have previously shown that the bacterial enzyme thiaminase 1 has antitumor activity. In an attempt to make thiaminase I a more effective pharmaceutical agent, we have modified it by adding polyethylene glycol (PEG) chains of various lengths. We were surprised to find that 5k-PEGylation eliminated thiaminase cytotoxic activity in all cell lines tested. Both native thiaminase and 5k-PEGylated ...

Poly(ethylene glycol)-conjugated (or PEGylated) proteins are an increasingly important class of therapeutic proteins that offer improved in vivo circulation half lives over their corresponding native forms. Their production involves covalent attachment of one or more poly(ethylene glycol) molecules to a native protein, followed by purification. Because of the extremely high costs involved in pr...