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


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: 

AmineThiolAldehyde, ketone, carboxylate, or phosphateClick reaction

Alexa Fluor 555 protein/antibody labeling kits

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

Alexa Fluor Dye stained cell

Alexa Fluor dye family

Alexa Fluor dyes are among the most trusted fluorescent dyes available today. Learn more about the:

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

Brilliant Ultra Violet™ and Brilliant Violet™ are trademarks or registered trademarks of Becton, Dickinson and Company or its affiliates, and is used under license.

For Research Use Only. Not for use in diagnostic procedures.