Sulfo DBCO-PEG3-NHS ester is a click chemistry reagent featuring an azide group. It serves as an analog of DBCO-acid, incorporating a PEG linker and a DBCO group. The DBCO group is often utilized in copper-free click reactions due to its high-energy strain. The hydrophilic polyethylene glycol chain and sulfo group enhance its water solubility. The terminal carboxylic acid can react with primary amine groups to form stable amide bonds in the presence of activators such as EDC or HATU. This is a reagent-grade compound intended solely for research purposes.