Tetrazines demonstrate exceptionally fast cycloaddition kinetics (up to 30 000 M-1 s-1) with trans-cyclooctenes (TCO) as the dienophile, the fastest kinetics ever reported for any bioorthogonal reaction. In addition, inverse-Electron-Demand Diels-Alder reaction of tetrazines trans-cyclooctenea forms a stable covalent bond and does not require Cu-catalyst or elevated temperatures. In applications such as in vivo cancer imaging or pre‐targeted cell labeling studies where rapid reaction kinetics is a must, a faster hydrogen substituted Cy®5 Tetrazine probe would be a probe of choice.
Terazine-activated Cy5 dye reacts with TCO-containing compounds via a Inverse-Electron-Demand Diels-Alder reaction to form a stable covalent bond and does not require Cu-catalyst or elevated temperatures. The inverse-electron demand Diels-Alder cycloaddition reaction of TCO with tetrazines is a bioorthogonal reaction that possesses exceptional kinetics and selectivity. Such excellent reaction rate constants are unparalleled by any other bioorthogonal reaction pair described to date.
Cy5 Tetrazine is a water-soluble, pH-insensitive from pH 4 to pH 10, far-red-fluorescent probe with excitation ideally suited for the 633 nm or 647 nm laser lines. Its absorption and emission spactra are almost identical to those of Alexa Fluor® 647, CF® 647 Dye, or any other Cyanine5 based fluorescent dyes.
This is sulfonated dye is also known as sulfo-Cyanine5.