ATTO 425 DBCO

• Ex/Em: 438/484 nm
• Extinction coefficient: 45,000 cm^-1M^-1
• Reactive group: DBCO
• Copper-Free Bioorthogonal Labeling: Enables efficient azide conjugation via SPAAC without copper, ideal for sensitive systems
• Superior Brightness & Stability: Delivers robust, steady fluorescence for sensitive applications
• Enhanced Signal Separation: Minimal excitation and emission overlap reduces background interference

ATTO 425 is a coumarin-based fluorescent dye characterized by its high fluorescence quantum yield, large Stokes shift, excellent photostability, and low molecular weight. It exhibits moderate hydrophilicity and is optimally excited in the 405-455 nm wavelength range. These properties make ATTO 425 particularly suitable for applications in single-molecule detection and high-resolution microscopy techniques, including PALM, dSTORM, and STED microscopy. Additionally, ATTO 425 is well-suited for use in flow cytometry (FACS), fluorescence in situ hybridization (FISH), and various other biological assays.

The DBCO derivative of ATTO 425 is a highly reactive cycloalkyne optimized for copper-free click chemistry (SPAAC, strain-promoted azide-alkyne cycloaddition). This derivative exhibits a significantly higher reaction rate with azides compared to other cyclooctynes and copper-catalyzed click reactions (CuAAC). Uniquely, DBCO does not react with tetrazines, allowing for its use in bioorthogonal reactions alongside trans-cyclooctenes and tetrazines. For applications where the presence of copper is problematic, ATTO 425 DBCO serves as an effective alternative to copper-dependent fluorescent alkynes.