Which groups are on your target?
Consider NHS for primary amines and Maleimide for free thiols. For click chemistry, confirm the reaction partners first.
AF555 fluorescent dyes
Yellow emission, with 5 reactive dyes and 4 bioconjugates. Excitation near 561 nm and collection near 572 nm; find labeling methods and documents for the target handle.
555nm
572nm
9
Optical values refer to AF555 NHS.
AF555 NHS spectral referenceYellow
AF555 product selection
Find AF555 dyes and conjugates by reactive group or recognition ligand.
Which recognition ligand do you need?
Compare Annexin V, WGA, CTB, Streptavidin; check the sample and conditions.
| Product / catalog no. | Reactive form / ligand | Targets and applications | Documents |
|---|---|---|---|
| AF555 NHS EsterQH-10-1008 | NHS | Antibodies, proteins and other molecules with accessible primary amines | View product → |
| AF555 MaleimideQH-10-1008(Maleimide) | Maleimide | Targets with accessible free thiols | View product → |
| AF555 AzideQH-10-1008(Azide) | Azide | Targets with a compatible alkyne; confirm the click reaction system | View product → |
| AF555-PEG4-DBCOQH-10-1008(DBCO PEG4) | PEG4-DBCO | Azide coupling with a PEG4 spacer | View product → |
| AF555-PEG12-DBCOQH-10-1008(DBCO PEG12) | PEG12-DBCO | Azide coupling; evaluate a PEG12 spacer | View product → |
| AF555-Annexin VQH-10-1008(Annexin V) | Annexin V | Recognizes exposed PS; binding requires Ca²⁺ | View product → |
| AF555 WGAQH-10-1008(WGA) | WGA | Recognizes glycans containing GlcNAc or sialic acid | View product → |
| AF555 CTBQH-10-1008(CTB) | CTB | Recognizes GM1; consider binding and uptake conditions | View product → |
| AF555-StreptavidinQH-15-1007 | Streptavidin | Detect existing biotin labels using Streptavidin | View product → |
Showing 9 / 9 AF555 products
Spectra and detection conditions
AF555 NHS optical properties
- Reference product
- AF555 NHS · QH-10-1008
- Excitation peak
- 555 nm
- Emission peak
- 572 nm
- Molar extinction coefficient
- 155,000 M⁻¹ cm⁻¹
Values refer to this product’s specifications. Consult measurement records for solvent, pH and conjugation state.
Full product specifications →Excitation near 561 nm and collection near 572 nm
A 561 nm source is a candidate for evaluation; assess 543 nm excitation against actual spectra as well. Cy3 or TRITC presets do not define a universal optical path. Inspect the source, filters and detector configuration.
A 575/30 bandpass nominally spans 560–590 nm and includes the 572 nm emission peak. Collected signal depends on the full emission spectrum, filter transmission and detector response; this is a passband example. This example does not specify 561 nm laser blocking; use a filter set matched to the source and dichroic.
Read the detection guide →Multicolor combinations and controls
AF555 emission is very close to AF546 and may overlap Cy3-type collection windows. If a nearby-wavelength label is already present, first assess separation. Reaction activity, molecular weight and labeling calculations remain product-specific even for nearby spectral regions.
Multicolor detection considerations →Match the workflow to the target handle
Bioconjugates
For established recognition ligands, review the corresponding conjugates and their product-specific formulation, dose and storage conditions.
| Product | Recognition target and conditions |
|---|---|
| AF555-Annexin V | Phosphatidylserine; binding is Ca²⁺ dependent. |
| AF555 WGA | GlcNAc- or sialic-acid-containing glycans; consider sample preparation and intracellular signal. |
| AF555 CTB | GM1 ganglioside; confirm the application and treatment conditions. |
| AF555-Streptavidin | Biotinylated targets; account for competing free biotin. |
References
References on reaction chemistry, assay design and result interpretation.
Labeling a protein with fluorophores using NHS ester derivitization
Nanda JS, Lorsch JR. · Methods in Enzymology · 536:87–94 · 2014
Uses FAM ester labeling of a protein to explain primary-amine chemistry and labeling-efficiency assessment. It informs NHS workflow design; input and reaction conditions depend on the actual dye and sample.
Fluorescent-labeled antibodies: Balancing functionality and degree of labeling
Vira S, Mekhedov E, Humphrey G, Blank PS. · Analytical Biochemistry · 402(2):146–150 · 2010
Uses FITC-labeled anti-HA antibody to assess changes in labeling density and antigen binding. It informs input-series design and post-purification functional testing; DOL alone is insufficient for selecting a conjugate.
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.
Technical guides
AF555 · Labeling & detectionAF555 spectra and detection channelsAF555 NHS has 555/572 nm peaks. Check the excitation source, emission window and detector response separately.
Product peaks and excitation source
AF555 NHS has an excitation peak of 555 nm and an emission peak of 572 nm. Check the product name, source wavelength and collection window separately. A 561 nm source is a candidate for evaluation; assess 543 nm excitation against actual spectra as well. Cy3 or TRITC presets do not define a universal optical path. Inspect the source, filters and detector configuration.
Emission window and optical path
A 575/30 bandpass nominally spans 560–590 nm and includes the 572 nm emission peak. Collected signal depends on the full emission spectrum, filter transmission and detector response; this is a passband example. This example does not specify 561 nm laser blocking; use a filter set matched to the source and dichroic.
Confirm settings with measured signals
The peak-position figure cannot compare brightness or calculate compensation. Use measured spectra to inspect filter coverage, then unstained and single-stain samples to assess background and signal. Keep gain or exposure fixed when comparing samples.
References
Chroma · Optical filters and bandwidth
chroma.com
Thermo Fisher · Sources and detection regions
tools.thermofisher.com
AF555 · Labeling & detectionDetection windows for AF555, AF546 and Cy3Neighboring dyes can enter the same detection window. Use single stains to check cross-excitation, spillover and separation.
Detection windows for AF555, AF546 and Cy3
AF555 emission is very close to AF546 and may overlap Cy3-type collection windows. If a nearby-wavelength label is already present, first assess separation. Reaction activity, molecular weight and labeling calculations remain product-specific even for nearby spectral regions.
Establish separation with controls
Measure each single-stain sample in every relevant channel and use an unstained sample for baseline fluorescence. Set conventional-flow compensation from these measurements or use dye- and treatment-matched references for spectral unmixing. If signals remain poorly resolved, change the dye panel or detection windows.
Comparison of products in similar regions
When comparing dye conjugates of the same target, match target concentration and labeling density and record each source and filter. A brighter reading in one channel may reflect better excitation or collection. Compare specific signal, background, recovery and function alongside raw intensity.
References
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
Chroma · Optical filters and bandwidth
chroma.com
Labeling guide
Read guide →NHS and maleimide labeling routes
NHS labels primary amines; maleimide labels free thiols. Additives and reduction requirements determine sample preparation.
Labeling guide
Read guide →Azide and DBCO click-reaction pairing
Terminal alkynes pair with azides through CuAAC; DBCO pairs with azides through copper-free SPAAC.
Labeling guide
Read guide →Assessment of AF555-labeled conjugates
Compare labeling density, sample recovery, specific signal and background after purification, rather than total fluorescence alone.
Product-specific documents
Instructions, SDS, product specifications and CoA are catalog-specific. Request documents on the corresponding product page and include the vial lot number for a CoA.
AF555 NHS Ester
QH-10-1008
AF555 Maleimide
QH-10-1008(Maleimide)
AF555 Azide
QH-10-1008(Azide)
AF555-PEG4-DBCO
QH-10-1008(DBCO PEG4)
AF555-PEG12-DBCO
QH-10-1008(DBCO PEG12)
AF555-Annexin V
QH-10-1008(Annexin V)
AF555 WGA
QH-10-1008(WGA)
AF555 CTB
QH-10-1008(CTB)
AF555-Streptavidin
QH-15-1007
Spectral and selection support
Include the target, reactive handles, buffer formulation, excitation source and emission window to help identify the product and supporting measurement information.
FAQ
How does the AF555 name relate to excitation and emission?
AF555 NHS has an excitation peak of 555 nm and an emission peak of 572 nm. Check the product name, source wavelength and collection window separately.
Can Cy3 labeling calculations be reused for AF555?
Nearby detection windows do not establish identical chemistry. Dosing requires the molecular weight of the AF555 reactive form; labeling calculations also need its extinction coefficient and absorption corrections. Request missing parameters first.
Can AF555 be combined with neighboring dyes?
AF555 emission is very close to AF546 and may overlap Cy3-type collection windows. If a nearby-wavelength label is already present, first assess separation. Reaction activity, molecular weight and labeling calculations remain product-specific even for nearby spectral regions.
How do NHS, Maleimide, Azide and DBCO match targets?
Use NHS for primary amines, Maleimide for free thiols, Azide for terminal or strained alkynes, and PEG4-DBCO or PEG12-DBCO for azides. Each product page covers pretreatment, buffer and purification requirements.
Can reactive dyes and bioconjugates share storage conditions?
Follow each product page and vial label. Reactive dyes in this catalog are stored dry at −20°C and protected from light; aqueous conjugates have separate requirements. Prepared dye solutions and newly made conjugates cannot simply inherit dry-dye storage conditions.
Can molecular weight, CAS or extinction coefficients be borrowed from a similar dye?
Do not borrow these values. Reactive form, spacer, structure and salt form can affect them; confirm by catalog number. Request missing identity and calculation parameters through the product Documents tab rather than inferring them from a similar name.
How can I obtain instructions, measured spectra and a lot CoA?
Use Documents on the specific product page and describe the application and detection settings. Supply the catalog and vial lot numbers for a CoA. The displayed spectrum is a peak schematic and references concern methods; neither is a lot inspection result.