N-Mal-N-bis(PEG4-NHS ester) is a branched PEG linker with two terminal carboxylic acids and a maleimide group. The terminal carboxylic acids can be reacted with primary and secondary amino groups in the presence of EDC, DCC, HATU and other coupling reagents to form stable amide bonds. The maleimide group reacts specifically with a cysteine thiol group to form a covalent S-C bond, making it an ideal conjugation tool for cysteine residues.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.