Cy3B Tetrazine

Cy3® dye is one of the most common cyanine dyes used for labeling proteins, nucleic acids and other biological molecules. A variety of Cy3® dyes has been used to label biological molecules for fluorescence imaging and other fluorescence-based biochemical analysis. They are widely used for labeling peptides, proteins and oligos etc. However, Cy3 suffers low fluorescence intensity. It is the least fluorescent dyes among all the Cy dyes. Cy3B is an improved version of Cy3 dyes with significantly increased fluorescence quantum yield and photostability. Cy3B tetrazine can be used for conjugations with TCO-containing biological molecules under copper-free conditions. Compared to the other click reactions, the TCO-tetrazine reaction gives much higher yields under mild reaction conditions. Cy3® is the trademark of GE Healthcare.

Spectrum

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Product family

Name	Excitation (nm)	Emission (nm)	Extinction coefficient (cm ^-1 M ^-1)	Quantum yield	Correction Factor (260 nm)	Correction Factor (280 nm)
Cy3 tetrazine	555	569	150000¹	0.15¹	0.07	0.073
Cy3B acid	560	571	120000¹	0.58¹	0.048	0.069
Cy3B alkyne	560	571	120000¹	0.58¹	0.048	0.069
Cy3B azide	560	571	120000¹	0.58¹	0.048	0.069
Cy3B DBCO	560	571	120000¹	0.58¹	0.048	0.069
Cy3B maleimide	560	571	120000¹	0.58¹	0.048	0.069
Cy3B TCO	560	571	120000¹	0.58¹	0.048	0.069
Cy5 tetrazine	651	670	250000¹	0.27¹, 0.4²	0.02	0.03

Citations

View all 2 citations: Citation Explorer

Triple Labeling Resolves a GPCR Intermediate State by Using Three-Color Single Molecule FRET
Authors: Bonhomme, L{\'e}o and Bilgen, Ecenaz and Clert{\'e}, Caroline and Pin, Jean-Philippe and Rondard, Philippe and Margeat, Emmanuel and Lamb, Don C and Quast, Robert B
Journal: Journal of the American Chemical Society (2025)

Structural basis of orientated asymmetry in a mGlu heterodimer
Authors: Huang, Weizhu and Jin, Nan and Guo, Jia and Shen, Cangsong and Xu, Chanjuan and Xi, Kun and Bonhomme, L{\'e}o and Quast, Robert B and Shen, Dan-Dan and Qin, Jiao and others,
Journal: Nature Communications (2024): 1--15

References

View all 37 references: Citation Explorer

Fluorescence Anisotropy-Based Assay for Characterization of Ligand Binding Dynamics to GPCRs: The Case of Cy3B-Labeled Ligands Binding to MC4 Receptors in Budded Baculoviruses.
Authors: Veiksina, Santa and Tahk, Maris-Johanna and Laasfeld, Tõnis and Link, Reet and Kopanchuk, Sergei and Rinken, Ago
Journal: Methods in molecular biology (Clifton, N.J.) (2021): 119-136

Quantitative analysis of fluorescent ligand binding to dopamine D3 receptors using live-cell microscopy.
Authors: Allikalt, Anni and Laasfeld, Tõnis and Ilisson, Mihkel and Kopanchuk, Sergei and Rinken, Ago
Journal: The FEBS journal (2021): 1514-1532

Fluorescent ligands for dopamine D2/D3 receptors.
Authors: Allikalt, Anni and Purkayastha, Nirupam and Flad, Khajidmaa and Schmidt, Maximilian F and Tabor, Alina and Gmeiner, Peter and Hübner, Harald and Weikert, Dorothee
Journal: Scientific reports (2020): 21842

Unifying Mechanism for Thiol-Induced Photoswitching and Photostability of Cyanine Dyes.
Authors: Gidi, Yasser and Payne, Liam and Glembockyte, Viktorija and Michie, Megan S and Schnermann, Martin J and Cosa, Gonzalo
Journal: Journal of the American Chemical Society (2020): 12681-12689

Fluorescence lifetime imaging with a single-photon SPAD array using long overlapping gates: an experimental and theoretical study.
Authors: Ardelean, Andrei and Ulku, Arin Can and Michalet, Xavier and Charbon, Edoardo and Bruschini, Claudio
Journal: Proceedings of SPIE--the International Society for Optical Engineering (2019)

Page updated on May 19, 2025

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Catalog Number	948
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Physical properties

Molecular weight	729.86
Solvent	DMSO

Spectral properties

Correction Factor (260 nm)	0.048
Correction Factor (280 nm)	0.069
Extinction coefficient (cm ^-1 M ^-1)	120000¹
Excitation (nm)	560
Emission (nm)	571
Quantum yield	0.58¹

Storage, safety and handling

H-phrase	H303, H313, H333
Hazard symbol	XN
Intended use	Research Use Only (RUO)
R-phrase	R20, R21, R22
Storage	Freeze (< -15 °C); Minimize light exposure
UNSPSC	12171501