ATTO 390 DBCO

• Ex/Em: 390/475 nm
• Extinction coefficient: 24,000 cm^-1M^-1
• Reactive group: DBCO
• Copper-Free Bioorthogonal Labeling: Enables efficient azide conjugation via SPAAC without copper, ideal for sensitive systems
• Enhanced Brightness & Stability: Delivers robust, steady fluorescence for sensitive applications
• Large Stokes Shift: Enables effective signal separation, reducing background interference

ATTO 390 is a coumarin-based fluorescent dye characterized by its high fluorescence quantum yield, large Stokes shift, good photostability, and low molecular weight. It exhibits moderate hydrophilicity and is optimally excited within the 360-410 nm range, with a mercury arc lamp (emission lines at 365 nm and 405 nm) serving as an effective excitation source. This dye is well-suited for applications in single-molecule detection and advanced high-resolution microscopy techniques, including PALM, dSTORM, and STED. Additionally, ATTO 390 is compatible with flow cytometry (FACS), fluorescence in situ hybridization (FISH), and other diverse biological assays.

The DBCO derivative of ATTO 390 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 390 DBCO serves as an effective alternative to copper-dependent fluorescent alkynes.