m-PEG4-(CH2)3-acid linker contains a terminal carboxylic acid. The terminal carboxylic acid readily reacts with primary and secondary amine under EDC, DCC, HATU or other amide coupling conditions to form a stable amide bond. The mPEG modification increases the aqueous solubility of the resulting compound.
AxisPharm offers 4000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.