N-(Azido-PEG3)-N-(PEG2-amine)-PEG3-acid is a heterotrifunctional PEG linker containing azide (N3), amine(NH2), and carboxylic acid(CO2H) moieties. The azide can react with alkyne, BCN, DBCO via Click Chemistry to yield a stable triazole linkage. An amine is reactive with carboxylic acids, activated NHS esters, carbonyls (ketone, aldehyde) etc. The terminal carboxylic acid can react with primary amine groups in the presence of activators (e.g. EDC, or HATU) to form a stable amide bond.
