TCO-PEG3-acid is a click chemistry PEG linker with a terminal carboxylic acid(CO2H) group. The terminal carboxylic acid is reactive with primary amine groups in the presence of activators (e.g. EDC, or HATU) to form a stable amide bond. This reagent can react with tetrazine-containing compounds to form a stable covalent bond. The inverse-electron demand Diels-Alder cycloaddition reaction of TCO with tetrazines is the fastest bioorthogonal reaction with exceptional selectivity. Reagent grade, for research purpose. Please contact us for GMP-grade inquiries.