TCO-PEG4-TFP Ester

TCO-PEG4-TFP Ester is an amine-reactive, labeling reagent used to modify proteins, antibodies, and other amine-containing biopolymers. The hydrophilic polyethylene glycol (PEG) spacer arm imparts water solubility and provides a long and flexible connection that minimizes steric hindrance involved with ligation to complementary tetrazine-containing molecules.

The N-hydroxysuccinimide (NHS, also known as HOSu) esters of carboxylic acids are the most widely used reactive esters for modifying amine-containing peptides and proteins. NHS esters are notorious for having a short, pH-dependent half-life in aqueous media. A 2,3,5,6-tetrafluorophenol (TFP) is a different type of reactive ester that displays much better stability toward hydrolysis in aqueous media resulting in more efficiency and better reproducible labeling of biopolymers. TFP ester of carboxylic acids react with primary amines at the same rate as NHS ester forming covalent amide bond that is identical to one formed by the reaction between primary amines and NHS esters or sulfo-NHS esters.