Azido-PEG4-NHS Ester

Azido-PEG4-NHS Ester is a labeling reagent that can be used to modify primary amine groups (e.g., a side chain of lysine residues or aminosilane-coated surfaces) with an azido group via a stable amide bond. The azide (N3) group reacts with terminal alkynes via CuAAC, strained cyclooctynes (e.g. DBCO or BCN compounds) via Cu-free click reaction or with phosphine-labeled molecules by a mechanism known as Staudinger chemistry, enabling efficient and specific conjugation of derivatized molecules in biological samples.