CY3-SE  (Synonyms: Sulfo-Cy3 NHS ester; Sulfo Cyanine3 NHS ester)

Cy3-SE (Sulfo-Cy3 NHS ester; Sulfo Cyanine3 NHS ester) is a sulfonated cyanine dye-derived fluorescent labeling reagent with λ_ex of about 515 nm and λ_em of about 568 nm. Cy3-SE can interact with the π-π stacking of biomolecules (e.g., nucleoside monophosphates, proteins), inhibiting the photoisomerization process and increasing the fluorescence quantum yield and lifetime^[1][2].

In the presence of nucleoside monophosphates (dNMPs) in solution, Cy3-SE inhibits photoisomerization through π-π stacking interactions, significantly increasing the fluorescence efficiency and lifetime. It has a better enhancement effect on purines (dAMP, dGMP) than on pyrimidines (dCMP, dTMP)^[1].
Guidelines (Following is our recommended protocol. This protocol only provides a guideline, and should be modified according to your specific needs).
1. Dissolution: Dissolve Cy3-SE in DMSO or other suitable organic solvents to prepare a stock solution;
2. Reaction: Dissolve the target molecule (e.g., peptide, antibody) in a buffer solution (e.g., 5 mM PBS, pH 8.0), add an equimolar or excess amount of Cy3-SE solution, and react at room temperature in the dark for 4-6 hours;
3. Purification: Remove unreacted Cy3-SE by dialysis (molecular weight cutoff 2000 Da) or high performance liquid chromatography (HPLC), and collect the labeled product.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

727.84

C₃₅H₄₁N₃O₁₀S₂

146368-16-3

Solid

Brown to red

570

550

CC(/C(N1CCCCCC(ON2C(CCC2=O)=O)=O)=C\C=C\C3=[N+](CC)C(C=CC(S(=O)([O-])=O)=C4)=C4C3(C)C)(C)C5=C1C=CC(S(=O)(O)=O)=C5

Room temperature in continental US; may vary elsewhere.

-20°C, sealed storage, away from moisture and light

*In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture and light)

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture and light). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

• [1]. Harvey BJ, et al. Nucleobase-specific enhancement of Cy3 fluorescence. J Fluoresc. 2009 May;19(3):443-8.  [Content Brief]

  [2]. Dang YQ, et al. Construction of a supramolecular Förster resonance energy transfer system and its application based on the interaction between Cy3-labeled melittin and phosphocholine encapsulated quantum dots. ACS Appl Mater Interfaces. 2012 Mar;4(3):1267-72.  [Content Brief]