TCO-PEG24-acid is a monodisperse, aqueous soluble PEG reagent with a TCO moiety. Carboxylic acid (CO2H) can react with primary amine groups in the presence of activators. TCO is very reactive with tetrazine-containing molecule. The inverse-electron demand Diels-Alder cycloaddition of TCO with tetrazines is the fastest bioorthogonal reaction with exceptional selectivity. The hydrophilic PEG spacer increases solubility in aqueous media. Reagent grade, for research purpose. Please contact us for GMP-grade inquiries.