N3-PEG5-CH2CO2-NHS

Azido-PEG5-CH2CO2-NHS is a very active pegylation reagent with 5 PEG units. The hydrophilic PEG spacer increases solubility in aqueous media. The azide group allows the reaction with alkyne, BCN, DBCO via Click Chemistry to yield a stable triazole linkage. The NHS ester can be used to label the primary amines (-NH2) of proteins, amine-modified oligonucleotides, and other amine-containing molecules.