SUNBRIGHT ME-050AL is a methoxy PEG aldehyde with a 5,000 Da PEG chain. The aldehyde group selectively reacts with amine or aminooxy groups on bioactive molecules. By leveraging the pKa difference between the ε-amine of lysines and the α-amine of the N-terminus, the aldehyde group can be used for selective PEGylation under slightly acidic conditions (pH 4.5–6). This approach minimizes off-target reactions at lysine side chains, allowing preferential conjugation at the protein’s N-terminus and resulting in more homogeneous PEG–protein conjugates. Moreover, the initial Schiff base (imine) formed upon reaction with amine groups can be stabilized via reductive amination to yield a stable secondary amine linkage. This N-terminal PEGylation strategy has been employed in the development of commercial therapeutics such as Neulasta® (pegfilgrastim) and its biosimilars, demonstrating its utility and commercial viability in the biopharmaceutical field.
Methoxy-PEG-(CH2)2-CHO, Mw 5,000
Chemical Name: α-Methoxy-ω-(3-oxopropoxy), polyoxyethylene
CAS#: 125061-88-3
