N-(Amino-PEG4)-N-Biotin-PEG4-acid is a 3-arm biotinylation reagent with terminal amine(NH2) and carboxylic acid moieties. The amine group can react with activated NHS esters. Carboxylic acid can conjugate with primary amines in the presence of activators such as EDC or HATU to form stable amide bonds.
