Alexa Fluor® 568 dyeAlexa Fluor® 568 dye is a bright, orange-fluorescent dye with excitation ideally suited for the 568 nm laser line on the Ar-Kr mixed-gas laser. For stable signal generation in imaging and flow cytometry, Alexa Fluor® 568 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® 568 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® 568 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® 568 dye dashboard

Initial brightness

Bright and photostable orange-red dye that matches well with RFP filter sets. In addition, is used in stochastic optical reconstruction microscopy (STORM)—as a reporter in dSTORM.

Photostability in buffer


Photostability in antifade


Performance in SRM


  568 Texas Red® 578 603  
Laser line

Common filter set

Excitation max

Emission max


Alexa Fluor® 568 reactive dyes

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

Amine Thiol Aldehyde, ketone, carboxylate, or phosphate

Alexa Fluor® 568 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® 568 Mouse IgG1 Labeling Kit Z25006
<1–20 µg mouse IgG2a Zenon® Alexa Fluor® 568 Mouse IgG2a Labeling Kit Z25106
<1–20 µg rabbit IgG Zenon® Alexa Fluor® 568 Rabbit IgG Labeling Kit Z25306
Conventional antibody/protein labeling
10–20 µg antibody APEX™ Alexa Fluor® 568 Antibody Labeling Kit A10494
100 µg antibody/protein Alexa Fluor® 568 Antibody/Protein Labeling Kit A20184
1 mg antibody/protein Alexa Fluor® 568 Antibody/Protein Labeling Kit A10238

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® 568 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.