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Chemical structure for Cy3B TCO.
Chemical structure for Cy3B TCO.
Ordering information
Price ()
Catalog Number946
Unit Size
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Additional ordering information
InternationalSee distributors
ShippingStandard overnight for United States, inquire for international
Physical properties
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 yield0.581
Storage, safety and handling
H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22
StorageFreeze (< -15 °C); Minimize light exposure
Direct upgrades
iFluor® 555 TCO


Correction Factor (260 nm)
Correction Factor (280 nm)
Extinction coefficient (cm -1 M -1)
Excitation (nm)
Emission (nm)
Quantum yield
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 TCO can be used for conjugations with tetrazine-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.


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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 yield0.581

Product family

NameExcitation (nm)Emission (nm)Extinction coefficient (cm -1 M -1)Quantum yieldCorrection Factor (260 nm)Correction Factor (280 nm)
Cy3B acid56057112000010.5810.0480.069
Cy3B maleimide56057112000010.5810.0480.069
Cy3B azide56057112000010.5810.0480.069
Cy3B alkyne56057112000010.5810.0480.069
Cy3B DBCO56057112000010.5810.0480.069
Cy3B Tetrazine56057112000010.5810.0480.069
XFD488 TCO499520730000.9210.30.11


View all 3 references: Citation Explorer
Design, Synthesis, Conjugation, and Reactivity of Novel trans,trans-1,5-Cyclooctadiene-Derived Bioorthogonal Linkers.
Authors: Longo, Beatrice and Zanato, Chiara and Piras, Monica and Dall'Angelo, Sergio and Windhorst, Albert D and Vugts, Danielle J and Baldassarre, Massimiliano and Zanda, Matteo
Journal: Bioconjugate chemistry (2020)
Clickable Methyltetrazine-Indocarbocyanine Lipids: A Multicolor Tool Kit for Efficient Modifications of Cell Membranes.
Authors: Gaikwad, Hanmant and Wang, Guankui and Smith, Weston J and Alexander, Keisha L and D'Alessandro, Angelo and Zhang, Wei and Purev, Enkhtsetseg and Simberg, Dmitri
Journal: Bioconjugate chemistry (2019): 2106-2114
Azide and trans-cyclooctene dUTPs: incorporation into DNA probes and fluorescent click-labelling.
Authors: Ren, Xiaomei and El-Sagheer, Afaf H and Brown, Tom
Journal: The Analyst (2015): 2671-8