Product manual
Product use, preparation, operating conditions and storage.
Tandem dyesFluorescent protein
RPE-Cy5.5
Cat. No.QH-50-5005
A fluorescent-protein donor and dye acceptor tandem for developing conjugates matched to the intended detection channel.
Packs & quoteDonor
Donor excitationTransfer
Donor → acceptorAcceptor
Acceptor emissionExcitation565 nm
Emission694 nm
TargetMolecules coupled through a suitable conjugation route
Preparation and storage
- Preparation
- Aqueous formulation
- Storage
- Store at 2–8°C, protect from light. Do not freeze
Tandem energy transfer
After donor excitation, energy is transferred to the acceptor. Light, fixation and storage can alter this relationship, changing acceptor signal and donor leakage. Compensation or unmixing references should match reagent lot and processing.
Fluorescent-conjugate development
After preparing the target conjugate, assess binding, free fluorescent-protein carryover and aggregation.
Multicolor detection
Configure the detection channel from this reagent’s optical properties, lasers and filters, then establish single-stain references.
Specifications
Product information
- Product name
- RPE-Cy5.5
- Cat. No.
- QH-50-5005
- Product form
- Tandem dyes
- Target
- Molecules coupled through a suitable conjugation route
- Pack sizes
- 1 mg / 5 mg / 10 mg / 25 mg / 100 mg
Preparation and properties
- Excitation wavelength
- 565 nm
- Emission wavelength
- 694 nm
- Molar extinction coefficient
- 1,960,000 M⁻¹ cm⁻¹
- Preparation and sample
- Aqueous formulation
- Storage
- Store at 2–8°C, protect from light. Do not freeze
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
Aqueous protein handling
Use an appropriate aqueous buffer for the formulation, avoiding organic solvents, harsh mixing and unsuitable freeze–thaw cycles.
Conjugation route
Check existing sites and any linker handles to be introduced. Do not use a fluorescent-protein reagent as though it were a small-molecule NHS dye.
Confirm activation state
Confirm by catalog number whether an activated handle is supplied and plan matching handles on the fluorescent material and target. Follow the supplied group for preactivated products, avoiding reactivation; remove free activator or reductant from each processed component.
PE donor and acceptor channels
This product uses a PE donor system. Check donor excitation, acceptor emission and acquisition windows by catalog number. The acceptor name does not specify donor excitation; monitor both acceptor signal and donor leakage in single stains.
Check protein condition
Check concentration, buffer and optical properties, including visible precipitation and aggregation.
Small-scale coupling
Use a validated activation and coupling procedure, titrating inputs and recording recovery and reaction conditions.
Resolve conjugate, free protein and aggregates
Both the fluorescent material and target antibody are macromolecules. Ordinary desalting or ultrafiltration does not ensure separation of the final conjugate from free fluorescent protein. Validate the resolving power of size-exclusion or another method, then assess recovery, purity and function.
Evaluate detection and storage
Compare initial and stored acceptor signal and donor-channel leakage, using lot- and processing-matched single stains for compensation or unmixing.
Request product documentation
Select a document and enter your phone and email. Include the lot number for a CoA.
RPE-Cy5.5QH-50-5005
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
Unconjugated and negative samples
Compare free protein and the target conjugate to assess nonspecific adsorption.
Single-stain reference
Use matching references for each lot and fixation treatment rather than automatically substituting another same-name lot.
Unlabeled sample
Use an unlabeled aliquot from the same preparation to assess changes in function, aggregation and recovery.
References
Tandem-dye donor leakage, processing stability and controls
R&D Systems · Tandem Dye-Conjugated Antibodies FAQs
The source concerns conjugated antibodies and informs energy transfer, degradation and lot-matched controls. Qihe’s tandem series contains labeling reagents; validate the final conjugate with lot- and process-matched single stains. The source is not a raw-reagent conjugation recipe.
Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)
Cossarizza A, Chang HD, Radbruch A, et al. · European Journal of Immunology · 51(12):2708–3145 · 2021
Provides methodological guidance on detection settings, controls and experimental records for downstream conjugate evaluation.
Frequently asked questions
Can it be used as a specific antibody?
It is a fluorescent-protein or tandem reagent. Specific recognition requires a suitable antibody or targeting molecule.
Can it be prepared in DMSO like a small dye?
Fluorescent proteins require structural preservation. Follow the aqueous formulation rather than small reactive-dye stock methods.
Can fixation alter channel behavior?
Tandems can be affected by fixation and storage. Compare acceptor and donor channels through the complete process and verify single-stain references.
Should a preactivated reagent be activated again?
First identify the supplied reactive group, then prepare a matching target handle. Reactivation can change handle density and protein condition; the reagent name alone does not establish activation.
Can another same-name lot replace the single-stain reference?
Acceptor composition, processing and storage can affect tandem spectra. Use the actual conjugate with lot- and processing-matched references for compensation or unmixing, and recheck after fixation or storage changes.