Benzyloxy carbonyl-PEG4-acid contains a benzyl protected carboxylic acid group and a carboxylic acid group. While the carboxylic acid group can react with primary amine groups in the presence of EDC, DCC or other coupling reagents to form a stable amide bond, the benzyl groups can be removed under mild condition to form another carboxylic acid for a secondary conjugation with amine-bearing biomolecules. The hydrophilic PEG linker increases the solubility of the compound in aqueous media.
AxisPharm offers 4000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.