Fluorescent Protein Labeling

The attachment of fluorescent dyes to proteins and other biomolecules is a common strategy used to better understand protein structure and function. These fluorescent proteins can used in a broad range of applications including immunochemistry, fluorescence in situ hybridization (FISH), cell tracing, receptor labeling and fluorescence spectroscopy to name a few. Thermo Fisher Scientific offers an assortment of solutions to prepare fluorescent protein and antibody bioconjugates including labeling kits, stand-alone dyes and custom labeling services.


What type of protein do you want to label with a fluorescent dye?

Antibodies

Find a wide selection of primary and secondary IgG antibody compatible labeling kits. Whether you are looking for site specific labeling strategies or are new to antibody labeling techniques, we have classic fluorophores and a broad range of Alexa Fluor dyes, Qdot nanocrystals and more in kit format.

Proteins

Non-IgG antibody proteins (mol. wt. ranging from 12 kDa to 150 kDa) can be fluorescently labeled with our protein labeling kits or using stand-alone amine- or thiol-reactive fluorescent dyes. Additionally, we offer custom labeling services.

Protein Labeling Kits

Protein Labeling Kits

Thermo Fisher Scientific Protein Labeling Kits provide a nearly effortless way to covalently label 1–10 mg protein (mol. wt. range of 12–150 kDa) with a fluorescent dye (including Alexa Fluor dyes) or biotin.

  • Label 1 mg protein
  • Three labeling reactions in each kit
  • Removal of BSA and other stablizers is required prior to labeling
  • Not compatible with amine-containing buffers (e.g. Tris)
  • Ready to use in 2 hours
  • ~ 30 minutes actual hands-on time

The Protein Labeling Kits utilize an amine-reactive fluorophore or hapten to covalently attach the label to the IgG antibody. Once formed, the covalent bond between the label and the protein is extremely stable—you are using the same chemistry we use to prepare our own primary and secondary conjugates.

Simply add ~ 1 mg purified protein (12—150 kDa) (in ~500 μL and free of amine-containing buffers such as Tris) to one of the vials containing a premeasured quantity of amine-reactive dye and a magnetic stir bar. Purification is accomplished on a gravity-feed size exclusion column supplied with the kit (Figure 1). The entire labeling and purification procedure can be completed in as little as 2 hours; everything needed to perform three conjugations is provided.

Figure 1. Protein Labeling Kits are the simplest way to label 1 mg of 150 kDa protein.

Protein Labeling Kits selection guide

Ex/Em = Fluorescence excitation and emission maxima, in nm.

Find more information about Alexa Fluor dyes and other fluorophores in the Fluorophore Selection Guide

TOP

Microscale Protein Labeling Kits

Microscale Protein Labeling Kits

Our Microscale Protein Labeling Kits conveniently label small amounts (20–100 μg) of purified protein with a bright, photostable Alexa Fluor dye or biotin-XX.

  • Labeled proteins ready in 2 hours, requiring approximately 30 minutes actual hands-on time
  • Label proteins with molecular weights between 12 and 150 kDa and quantities ranging from 20–100 µg

The Microscale Protein Labeling Kits use an amine-reactive fluorophore or biotin to covalently attach the label to the protein or IgG antibody. Once formed, the covalent bond between the label and the protein is extremely stable; you are using the same chemistry we use to prepare our own primary and secondary conjugates.

Unlike our other antibody labeling kits, these kits have been optimized for labeling proteins between 12 and 150 kDa, and so have utility in labeling antibodies as well as other proteins in that size range.

Any stabilizing proteins (e.g., BSA), must be removed prior to the labeling reaction. Convenient spin columns purify the labeled protein (Figure 2) with yields between 60 and 90%, depending on the molecular weight of the starting material. The entire labeling and purification procedure can be completed in as little as 2 hours—everything needed to perform three conjugations is provided in the kits.

Spin filter

Figure 2. Spin filter. (A) An empty filter showing the separate parts. (B) Appearance of the resin bed after centrifugation in a fixed-angle rotor or swinging bucket rotor.

Microscale Protein Labeling Kit selection guide

Label Ex/Em Cat. No.
Alexa Fluor 488 495/519 A30006
Alexa Fluor 555 555/565 A30007
Alexa Fluor 594 590/617 A30008
Alexa Fluor 647 650/665 A30009
Biotin-XX NA B30010
Biotin-XX (includes additional biotin quantitation assay) NA B30756

Ex/Em = Fluorescence excitation and emission maxima, in nm.

Find more information about Alexa Fluor dyes and other fluorophores in the Fluorophore Selection Guide

TOP

Protein Labeling Kits

Protein Labeling Kits

Thermo Fisher Scientific Protein Labeling Kits provide a nearly effortless way to covalently label 1–10 mg protein (mol. wt. range of 12–150 kDa) with a fluorescent dye (including Alexa Fluor dyes) or biotin.

  • Label 1 mg protein
  • Three labeling reactions in each kit
  • Removal of BSA and other stablizers is required prior to labeling
  • Not compatible with amine-containing buffers (e.g. Tris)
  • Ready to use in 2 hours
  • ~ 30 minutes actual hands-on time

The Protein Labeling Kits utilize an amine-reactive fluorophore or hapten to covalently attach the label to the IgG antibody. Once formed, the covalent bond between the label and the protein is extremely stable—you are using the same chemistry we use to prepare our own primary and secondary conjugates.

Simply add ~ 1 mg purified protein (12—150 kDa) (in ~500 μL and free of amine-containing buffers such as Tris) to one of the vials containing a premeasured quantity of amine-reactive dye and a magnetic stir bar. Purification is accomplished on a gravity-feed size exclusion column supplied with the kit (Figure 1). The entire labeling and purification procedure can be completed in as little as 2 hours; everything needed to perform three conjugations is provided.

Figure 1. Protein Labeling Kits are the simplest way to label 1 mg of 150 kDa protein.

Protein Labeling Kits selection guide

Ex/Em = Fluorescence excitation and emission maxima, in nm.

Find more information about Alexa Fluor dyes and other fluorophores in the Fluorophore Selection Guide

TOP

Microscale Protein Labeling Kits

Microscale Protein Labeling Kits

Our Microscale Protein Labeling Kits conveniently label small amounts (20–100 μg) of purified protein with a bright, photostable Alexa Fluor dye or biotin-XX.

  • Labeled proteins ready in 2 hours, requiring approximately 30 minutes actual hands-on time
  • Label proteins with molecular weights between 12 and 150 kDa and quantities ranging from 20–100 µg

The Microscale Protein Labeling Kits use an amine-reactive fluorophore or biotin to covalently attach the label to the protein or IgG antibody. Once formed, the covalent bond between the label and the protein is extremely stable; you are using the same chemistry we use to prepare our own primary and secondary conjugates.

Unlike our other antibody labeling kits, these kits have been optimized for labeling proteins between 12 and 150 kDa, and so have utility in labeling antibodies as well as other proteins in that size range.

Any stabilizing proteins (e.g., BSA), must be removed prior to the labeling reaction. Convenient spin columns purify the labeled protein (Figure 2) with yields between 60 and 90%, depending on the molecular weight of the starting material. The entire labeling and purification procedure can be completed in as little as 2 hours—everything needed to perform three conjugations is provided in the kits.

Spin filter

Figure 2. Spin filter. (A) An empty filter showing the separate parts. (B) Appearance of the resin bed after centrifugation in a fixed-angle rotor or swinging bucket rotor.

Microscale Protein Labeling Kit selection guide

Label Ex/Em Cat. No.
Alexa Fluor 488 495/519 A30006
Alexa Fluor 555 555/565 A30007
Alexa Fluor 594 590/617 A30008
Alexa Fluor 647 650/665 A30009
Biotin-XX NA B30010
Biotin-XX (includes additional biotin quantitation assay) NA B30756

Ex/Em = Fluorescence excitation and emission maxima, in nm.

Find more information about Alexa Fluor dyes and other fluorophores in the Fluorophore Selection Guide

TOP

Protein labeling with reactive dyes

We offer a wide selection of fluorescent dyes that can be used to fluorescently label proteins, including:

Protein labeling custom service

We also offer custom protein labeling services for both commercial and research use.

Looking for proteins that are already labeled with fluorescent dyes? Check out these options.

Fluorescent Secondary Antibodies

Fluorescent-dye conjugated secondary antibodies provide a much needed tool for identifying proteins in many applications including fluorescence imaging, western blotting, immunohistochemistry and more.

Biotin Binding Protein Conjugates

Streptavidin-based amplification techniques are widely used in flow cytometry, fluorescence imaging, western blotting, and microplate-based detection for increased signal output and greater sensitivity.

Other Fluorescent Protein Conjugates

Thermo Fisher Scientific offers a broad selection of fluorescent protein conjugates for basic research applications.

Looking to label other types of molecules with fluorescent dyes?