Alexa Fluor® 546 dyeAlexa Fluor® 546 dye is a bright, yellow-fluorescent dye that can be excited using the 488 nm or 532 nm laser lines. For stable signal generation in imaging and flow cytometry, Alexa Fluor® 546 dye is pH-insensitive over a wide molar range.

Probes with high fluorescence quantum yield and high photostability allow detection of low-abundance biological structures with great sensitivity. Alexa Fluor® 546 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® 546 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® 546 dye dashboard

Initial brightness




An alternative for tetramethylrhodamine or Cy®3 dye, with higher initial intensity than Alexa Fluor® 555 dye, but lower photostability in buffer or antifade.


Photostability in buffer


Photostability in antifade




  488/532 TRITC 556 573  
Laser line

Common filter set

Excitation max

Emission max

Alexa Fluor® 546 dye

The intermediate filaments in bovine pulmonary artery endothelial cells were visualized using our anti-desmin antibody, followed by Alexa Fluor® 647 goat anti–mouse IgG antibody (purple). Endogenous biotin in the mitochondria was labeled with Alexa Fluor® 546 streptavidin (red), and DNA in the cell was stained with DAPI (white).

Alexa Fluor® 546 reactive dyes

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

Amine Thiol

Alexa Fluor® 546 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® 546 Mouse IgG1 Labeling Kit Z25004
<1–20 µg rabbit IgG Zenon® Alexa Fluor® 546 Rabbit IgG Labeling Kit Z25304
Conventional antibody/protein labeling
100 µg antibody/protein Alexa Fluor® 546 Antibody/Protein Labeling Kit A20183
1 mg antibody/protein Alexa Fluor® 546 Antibody/Protein Labeling Kit A10237

Alexa Fluor® dye family

Illuminating research for over 15 years

Alexa Fluor® dyesAlexa 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

Molecular Probes HandbookThe 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.


Antifade reagents

Antifade reagentsAntifade reagents suppress photobleaching and preserve the signals of your fluorescently labeled target molecules. They offer excellent compatibility with Alexa Fluor® 546 dye and a multitude of dyes across the spectrum, making them especially valuable tools for multicolor applications.

Cell stain tool

Cell stain toolStain 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.


Fluorescence SpectraViewer

Fluorescence SpectraviewerPlot and compare spectra and check the spectral compatibility for common fluorophores including all the Molecular Probes® fluorescent probes. The Fluorescence SpectraViewer tool is formatted for both microscope imaging and flow cytometry applications.