Sulfo-DBCO-NHS ester is a click chemistry reagent containing an azide group. The DBCO group is commonly used for copper-free Click Chemistry reactions due to its strain promoted high energy. NHS ester can bind toamino acidsorothermolecules containing amino groups[1].
References:
[1].Takemoto H, et al. Accelerated polymer-polymer click conjugation by freeze-thaw treatment. Bioconjug Chem. 2012 Aug 15;23(8):1503-6.