Product manual
Product use, preparation, operating conditions and storage.
Cy5.5Reactive dye
Cy5.5 DBCO
Cat. No.QH-30-3004(DBCO)
Use copper-free SPAAC to label proteins, nucleic acids or materials carrying introduced azide handles.
Packs & quoteDBCO
Strained alkyneR–N₃
Azide handleTriazole
SPAAC linkageExcitation680 nm
Emission698 nm
TargetAccessible target-bound azide groups
Copper-free click coupling
DBCO is a strained alkyne that cycloadds to an azide. Ordinary unmodified proteins lack this paired handle; residual free azide reagents can consume DBCO.
Azide-modified proteins and antibodies
Introduce the azide and purify first, then compare coupling, background and function at matched molar inputs.
Modified nucleic acids and materials
Check azide density and accessibility. Include an azide-free surface control to assess adsorption.
Multicolor channels and near-infrared detection
Check the light source, filters and detector response against this catalog number’s wavelengths. For near-infrared forms, check detector sensitivity in that range; use separate single-color controls for adjacent Cy channels.
Specifications
Product information
- Product name
- Cy5.5 DBCO
- Cat. No.
- QH-30-3004(DBCO)
- Product form
- DBCO
- Target
- Accessible target-bound azide groups
- Pack sizes
- 1 mg / 5 mg / 10 mg / 25 mg / 100 mg
Preparation and properties
- Excitation wavelength
- 680 nm
- Emission wavelength
- 698 nm
- CAS
- 1857352-95-4
- Molar extinction coefficient
- 198,000 M⁻¹ cm⁻¹
- Quantum yield
- 0.2
- Storage
- Store at -20°C, protect from light and moisture
Spectral information and detection
Product parameters
Use parameters for the exact catalog number when preparing reagents, setting reagent input or calculating results. Request a lot-specific CoA for test results.
Protocol
Remove competing components
Remove free azide modification reagents. Review sodium azide and other additives, exchanging buffer when required.
Solubility and concentration
Prepare a stock using a supported solvent and check clarity after aqueous dilution. A PEG spacer or dye-family designation does not guarantee water solubility at every concentration.
Verify the azide sample
Confirm azide modification, sample concentration and removal of free reagent.
React without copper, protected from light
Use a compatible buffer, compare dye input and incubation time, and record the final solvent fraction and sample appearance.
Purification and analysis
Select desalting, size-exclusion separation, dialysis or chromatography for the sample size. Remove free reagent before measuring concentration, labeling density and function. Residual free dye raises background and biases labeling-density calculations.
Assess the product
Combine product analysis, a no-azide control and downstream function to assess coupling and adsorption.
Request product documentation
Select a document and enter your phone and email. Include the lot number for a CoA.
Cy5.5 DBCOQH-30-3004(DBCO)
Spectra and measurement conditions
Spectra, measurement conditions and detection settings for the exact catalog number.
Certificate of analysis (CoA)
Lot-specific test results. Include the lot number from the vial.
Safety data sheet (SDS)
Handling, storage and emergency response information.
Quality and lot information
No-azide control
Compare fluorescence after purification with an unmodified aliquot from the same sample to assess adsorption and free-dye carryover.
Unlabeled sample
Use an unlabeled aliquot from the same preparation to assess changes in function, aggregation and recovery.
Input titration
Compare a molar input series and assess signal, negative background, product recovery and function together.
Concentration and self-quenching
Excessive dye loading can cause self-quenching in protein conjugates. Compare purified conjugates made at lower inputs using equal protein amounts and common acquisition settings, assessing signal, background and binding rather than compensating for weak signal by adding more dye.
Technical articles
Application support
Include your sample, formulation and detection method when requesting application guidance.
References
Anomalous fluorescence enhancement of Cy3 and cy3.5 versus anomalous fluorescence loss of Cy5 and Cy7 upon covalent linking to IgG and noncovalent binding to avidin
Gruber HJ, Hahn CD, Kada G, et al. · Bioconjugate Chemistry · 11(5):696–704 · 2000
Compares fluorescence changes when Cy3, Cy3.5, Cy5 and Cy7 associate with IgG or avidin, informing joint assessment of labeling density and the purified conjugate’s signal.
DOI: 10.1021/bc000015m
Aza-dibenzocyclooctynes for fast and efficient enzyme PEGylation via copper-free (3+2) cycloaddition
Debets MF, van Berkel SS, Schoffelen S, et al. · Chemical Communications · 46(1):97–99 · 2010
Reports copper-free reaction of a strained alkyne with azides and its application to enzyme PEGylation.
DOI: 10.1039/b917797c
A Strain-Promoted [3 + 2] Azide–Alkyne Cycloaddition for Covalent Modification of Biomolecules in Living Systems
Agard NJ, Prescher JA, Bertozzi CR. · Journal of the American Chemical Society · 126(46):15046–15047 · 2004
Introduces ring-strain-driven azide–alkyne coupling without copper, a foundational study in SPAAC bioconjugation.
DOI: 10.1021/ja044996f
Frequently asked questions
Can it label an unmodified antibody directly?
Introduce azide handles first. DBCO is not a general labeling group for native amines or thiols.
Is a copper catalyst required?
DBCO–azide SPAAC does not require copper. Adding copper is not a general way to improve this reaction.
Can every PEG-containing product be dissolved in PBS?
A spacer alone does not establish this. Confirm solvent and concentration for the SKU and check for aqueous precipitation or aggregation.
Can Cy reactive forms share one parameter set?
Check wavelengths, solvent, molecular weight and correction data by catalog number. Reactive forms sharing a dye name can differ; retain the exact catalog number during selection and comparison.