Sulfo-Cy5 Azide，25MG，SML4341-25MG，Sigma

Biochem/physiol Actions

Sulfo-Cy5 Azide, a water-soluble and generally membrane-impermeable near-infrared (NIR) fluorescent reporter, is designed for bioorthogonal click chemistry, enabling efficient and specific attachment to alkyne or cyclooctyne-modified biomolecules like proteins, nucleic acids, and glycans with minimal non-specific binding. Its azide group reacts with terminal alkynes via Cu(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) or with strained cyclooctynes through Strain-Promoted Azide-Alkyne Cycloaddition (SPAAC), forming a stable, photo-stable triazole linkage that provides localized, sensitive fluorescence under mild conditions; notably, SPAAC is ideal for copper-free live-cell, real time imaging. This fluorescent labeling facilitates the visualization (through microscopy, flow cytometry, or in vivo imaging) and quantification of tagged molecules, thereby aiding studies in protein localization, nucleic acid tracking, and multiplex imaging. Characterized by spectral properties of λex ~646-651 nm, λem ~662-670 nm, Φ ~0.2, and ε ~250,000 M⁻¹cm⁻¹, Sulfo-Cy5 Azide serves as a versatile bioanalytical tool.