PEGylation

Slowly, I will move to this area of artificial protein modification. Here is a article recently I try to read.

Preparation and stability of N-terminal mono-PEGylated recombinant human endostatin (pubmed link)

The author fisrt pegylated endostatin with PEG-propionaldehyde derivatives. To find the optimal pegylation conditions, they used orthogonal tests with 4 factors, including pH, molar ratio of PEG to endostatin, temperature and time, in 3 levels.

After pegylation, they purified the mono-pegylated endostatin by CM sepharose FF cation exchange column.

Finally, the pegylated endostatin was analyzed in comparison to unmodified one. They found that pegylated endostatin is relatively resistant to proteolysis by trypsin and chymotrypsin. Pegylated endostatin is also more stable in high temperature (40-70C) and high pH (7-12).

As expected, the in vivo activity for antitumor is increase with pegylation.