TCO-PEG4-NHS ester is a bifunctional linker with trans-cyclooctene (TCO) and NHS ester groups flanking PEG4 (tetraethylene glycol).
The PEG spacer increases solubility in aqueous media and provides a long and flexible connection that minimizes steric hindrance involved with ligation.
The amine-reactive N-hydroxysuccinimide residue provides easy attachment to almost any primary or secondary amine group, such as protein, peptide, or small molecule amine.
Trans-cyclooctene readily reacts with tetrazines via inverse electron-demand Diels-Alder cycloaddition (IEDDA). TCO-Tetrazine ligation possesses ultrafast kinetics, selectivity, and long-term aqueous stability, which is important in low-concentration applications such as protein-protein conjugations, etc.
