ATTO 390 Tetrazine

• Ex/Em: 390/475 nm
• Extinction coefficient: 24,000 cm^-1M^-1
• Reactive group: Tetrazine
• Click Chemistry Conjugation: Provides rapid and copper-free labeling of TCO-modified biomolecules
• 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.

ATTO 390 tetrazine is particularly useful for labeling TCO-modified biomolecules under copper-free conditions. It reacts with TCO-functionalized molecules, forming a stable conjugate via a dihydropyrazine moiety. This click reaction is favored over others due to its extremely fast kinetics and higher yields under mild reaction conditions, making it a popular choice for researchers.