TCO-PEG*-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,*-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.
