N-(Azido-PEG4)-N-bis(PEG4-NHS ester)

N-(Azido-PEG4)-N-bis(PEG4-NHS ester) is a branched PEG derivative with a terminal azide group and two terminal NHS esters. The azide group enables PEGylation via Click Chemistry. The NHS esters can be used to label the primary amines (-NH2) of proteins, amine-modified oligonucleotides, and other amine-containing molecules.