A common way to synthesize an NHS-activated acid is to mix NHS with the desired carboxylic acid and a small amount of an organic base in an anhydrous solvent. A coupling reagent such as = dicyclohexylcarbodiimide (DCC) or ethyl(dimethylaminopropyl) carbodiimide (EDC) is then added to form a highly reactive activated acid intermediate. NHS reacts to form a less labile activated acid. The group itself is usually written as SuO- or  OSu in chemical nota on.

Such an ester with an acid and NHS, some times called succinate ester, is stable enough to be purified and stored at low temperatures in the absence of water and, as such, is commercially available. NHS esters are commonly used for protein modification (e.g. an NHS ester of fluorescein is commercially available, and can be added to a protein to obtain a fluorescently labeled protein in one simple reaction and purification step). NHS can be used with EDC to immobilize enzymes for biosensor applications.

Specifications: N-Hydroxysuccinimide