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Cy3B NHS ester

Chemical structure for Cy3B NHS ester.
Chemical structure for Cy3B NHS ester.
Ordering information
Price ()Discontinued
Catalog Number941
Unit Size
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Additional ordering information
InternationalSee distributors
ShippingStandard overnight for United States, inquire for international
Physical properties
Molecular weight657.74
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
Intended useResearch Use Only (RUO)
StorageFreeze (< -15 °C); Minimize light exposure


Molecular weight
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. Cy3 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. Cy3® is the trademark of GE Healthcare.


Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of Cy3B NHS ester to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

0.1 mg0.5 mg1 mg5 mg10 mg
1 mM152.036 µL760.179 µL1.52 mL7.602 mL15.204 mL
5 mM30.407 µL152.036 µL304.072 µL1.52 mL3.041 mL
10 mM15.204 µL76.018 µL152.036 µL760.179 µL1.52 mL

Molarity calculator

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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


View all 3 citations: Citation Explorer
Homogeneous fluorescence anisotropy-based assay for characterization of ligand binding dynamics to GPCRs in budded baculoviruses: the case of Cy3B-NDP-alpha-MSH binding to MC4 receptors
Authors: Veiksina, S., Kopanchuk, S., Mazina, O., Link, R., Lille, A., Rinken, A.
Journal: Methods Mol Biol (2015): 37-50
A highly fluorescent DNA toolkit: synthesis and properties of oligonucleotides containing new Cy3, Cy5 and Cy3B monomers
Authors: Hall, L. M., Gerowska, M., Brown, T.
Journal: Nucleic Acids Res (2012): e108
Cy3B: improving the performance of cyanine dyes
Authors: Cooper, M., Ebner, A., Briggs, M., Burrows, M., Gardner, N., Richardson, R., West, R.
Journal: J Fluoresc (2004): 145-50