Azido-PEG3-Sulfone-PEG4-acid is a PEG linker containing one azide group with a terminal carboxylic acid. The terminal carboxylic acid can react with primary amine groups in the presence of activators (e.g. EDC, or HATU) forming a stable amide bond. The azide group enables Click Chemistry. The hydrophilic PEG spacer increases solubility in aqueous media.
