Alexa Fluor® 555 dyeProbes with high fluorescence quantum yield and high photostability allow detection of low-abundance biological structures with great sensitivity. Invitrogen Alexa Fluor 555 dye molecules can be attached to proteins at high molar ratios without significant self-quenching, enabling brighter conjugates and more sensitive detection.

We offer Alexa Fluor 555 dye conjugated to a variety of antibodies, peptides, proteins, tracers, and amplification substrates optimized for cellular labeling and detection. In addition, reactive dye forms and protein labeling kits are available to allow you to generate your own antibody conjugates or probes.


Alexa Fluor 555 dye dashboard

Initial brightness

Recommended replacement for tetramethylrhodamine or Invitrogen Cy3 dye, exhibiting greater photostability than Cy3 dye in live and fixed cells. In addition, is used in stochastic optical reconstruction microscopy (STORM)—as an activator in nSTORM and a reporter in dSTORM.  

Photostability in buffer


Photostability in antifade


Performance in SRM


  488/532 TRITC 555 580  
Laser line

Common filter set

Excitation max

Emission max


Alexa Fluor® 555

A muntjac skin fibroblast was fixed and permeabilized. Mitochondria were labeled with anti–Oxphos Complex V inhibitor protein mouse IgG1 and visualized using orange-fluorescent Invitrogen Alexa Fluor 555 goat anti–mouse IgG. F-actin was labeled with green-fluorescent Invitrogen Alexa Fluor 488 phalloidin, and the nucleus was stained with Invitrogen TO-PRO 3 iodide (pseudocolored magenta).

Alexa Fluor 555 reactive dyes

Select dye-labeling chemistries for conjugation with the following reactive groups: 

Amine Thiol Aldehyde, ketone, carboxylate, or phosphate Click reaction

Alexa Fluor 555 protein/antibody labeling kits

Select an optimized labeling kit for your target antibody or protein:

Target protein Kit Cat. No.
Site-specific antibody labeling
<1–20 µg mouse IgG1 Zenon Alexa Fluor 555 Mouse IgG1 Labeling Kit Z25005
<1–20 µg mouse IgG2a Zenon Alexa Fluor 555 Mouse IgG2a Labeling Kit Z25105
<1–20 µg mouse IgG2b Zenon Alexa Fluor 555 Mouse IgG2b Labeling Kit Z25205
<1–20 µg rabbit IgG Zenon Alexa Fluor 555 Rabbit IgG Labeling Kit Z25305
Conventional antibody/protein labeling
10–20 µg antibody APEX Alexa Fluor 555 Antibody Labeling Kit A10470
20–100 µg antibody/protein Alexa Fluor 555 Microscale Antibody/Protein Labeling Kit A30007
100 µg antibody/protein Alexa Fluor 555 Antibody/Protein Labeling Kit A20187
1 mg antibody/protein Alexa Fluor 555 Antibody/Protein Labeling Kit A20174

Alexa Fluor dye family

Illuminating research for over 15 years

Alexa Fluor® dyesInvitrogen Alexa Fluor dyes are among the most trusted fluorescent dyes available today. In addition to superior performance, you’ll get a technical support team experienced in problem-solving, >50,000 published references, application and experimental tips, and protocols to help with experimental planning. For an outstanding research experience, choose Alexa Fluor dyes.



Molecular Probes Handbook

Cell stain tool

The significantly revised 11th Edition is the most complete fluorescence labeling and detection reference available. The Molecular Probes Handbook can help you achieve the best experimental results for your fluorescence labeling and detection experiments. View the handbook online or order your own copy.

Go to the Handbook online
Order your copy of the Handbook

Antifade reagents

Cell stain tool

Antifade reagents suppress photobleaching and preserve the signals of your fluorescently labeled target molecules. They offer excellent compatibility with a multitude of dyes across the spectrum, making them especially valuable tools for multicolor applications. For added convenience, some formulations include the nuclear counterstain DAPI, eliminating the need for a separate counterstaining step.

See the performance of this dye in SlowFade Antifade reagents
See the performance of this dye in ProLong Antifade reagents

Cell stain tool

Cell stain tool

Stain your own cell by using our simulation tool to develop reproducible results with many of our signature fluorescent dyes. Develop your multiplexing strategy for antibody probes, reactive dyes, and counterstains to create your perfectly labeled fluorescent cell.

Go to the cell stain tool

Fluorescence SpectraViewer


Plot and compare spectra and check the spectral compatibility for common fluorophores including all of the fluorescent probes from Thermo Fisher Scientific. The Fluorescence SpectraViewer tool is formatted for both microscope imaging and flow cytometry applications.

Go to the Fluorescence SpectraViewer

Not for resale. Super Bright Polymer Dyes are sold under license from Becton, Dickinson and Company.