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Invitrogen™ No-Stain™ Protein Labeling Reagent

Catalog No. A44717
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No. of Reactions:
10 reactions
40 reactions
Gel Compatibility:
Any Gel Type and Gel Chemistry
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Catalog No. No. of Reactions Gel Compatibility
A44717 10 reactions Any Gel Type and Gel Chemistry
A44449 40 reactions Any Gel Type and Gel Chemistry
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Catalog No. A44717 Supplier Invitrogen™ Supplier No. A44717
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A fast, easy to use, covalent protein labeling reagent, applied to a membrane after gel transfer that provides sensitive, linear detection of protein for total protein normalization of western blotting data. The Invitrogen No-Stain Reagent can also be used as a fast, sensitive gel stain for visualization of proteins in a gel.

The Invitrogen No-Stain Protein Labeling Reagent provides a flexible, accurate, rapid, and reliable method to visualize and normalize proteins in a gel or on a membrane (post-transfer). It forms covalent bonds to proteins in gels or on membranes within 10 minutes, does not require any de-staining steps, and can be instantly visualized using any commonly available imager. No-Stain reagent does not require any particular gels or other reagents and is compatible with gel stains and western workflows.

Instant visualization of proteins in gels

Coomassie and other gel staining and de-staining steps can be extremely time consuming and cumbersome. No-Stain Protein Labeling Reagent forms covalent bonds with the lysine amino acid side chains on all proteins in a gel within 10 minutes. Since lysine is one of the most abundant amino acids, No-Stain reagent enables detection of all proteins in a gel or on a membrane, and the strong signal emission from the covalently bonded reagent provides nanogram-level sensitivity.

  • Alternative to traditional gel staining reagents—provides more accurate normalization over a wide range of protein lysate concentrations (1–80 μg)
  • Sensitive—lower limit of detection of 20 ng per band
  • Specific—forms bonds only with the lysine side chains of proteins. Unbound reagent does not emit, thereby enabling a superior signal-to-noise ratio
  • Flexible—no need to change your gels to get stain-free convenience. No-Stain reagent provides stain-free convenience with any gel type (precast or pour-your-own gel)

Achieve the gold standard for quantitative western blotting

Protein normalization is a critical step in obtaining reliable and reproducible quantitative western blotting. Total protein normalization is considered the gold standard for quantitative western blotting. Many leading journals have developed guidelines for submitting western blotting research and select quotes from those guidelines are provided below.

  • 'For quantitative comparisons, appropriate reagents, controls and imaging methods with linear signal ranges should be used' – Nature
  • 'Record how data were obtained, whether signal intensity was linear with antigen loading, and how protein loading was normalized' – Journal of Biological Chemistry
  • 'Normalize signal intensity to total protein loading (assessed by staining membranes for total protein) whenever possible' – Journal of Biological Chemistry
  • 'House-keeping proteins should not be used for normalization without evidence that manipulations do not affect expression' – Journal of Biological Chemistry

An accurate loading control should display a linear relationship between signal intensity and sample load in all experimental conditions. The signal intensity obtained from labeling of total proteins on a membrane with No-Stain reagent ensures a linear relationship between signal intensity and sample load (see figure below) in all experimental conditions. Therefore, the use of No-Stain reagent in quantitative western blot applications enables the use of total protein as an ideal loading control.

  • Easy-to-use protocol—labeling of proteins within 10 minutes on either nitrocellulose or PVDF membranes
  • Rapid visualization using a wide-range of imagers with UV or fluorescence light sources
  • Accurate total protein normalization—the broad linear range for protein detection of 1–80 μg enables detection of No-Stain signal along with that of your target protein to achieve accurate total protein normalization
  • Sensitive and stable—nanogram level sensitivity with a stable signal that is compatible with downstream immunodetection steps
  • Superior analysis—housekeeping proteins are susceptible to signal saturation and other biological variations which are not observed when using No-Stain reagent for total protein normalization

Learn more about No-Stain Protein Labeling Reagent ›

Specifications

Product Line Invitrogen
Gel Compatibility Any Gel Type and Gel Chemistry
No. of Reactions 10 reactions
Membrane Compatibility Nitrocellulose, PVDF
Detection Method Fluorescence
Content And Storage • No-Stain activator, 200 μL, store at -5°C to -30°C
• No-Stain derivatizer, 200 μL, store at -5°C to -30°C
• No-Stain labeling buffer (20X), 2 x 5 mL, store at 15°C to 30°C
For Use With (Equipment) Compatible with wide-range of imagers with UV or Fluorescence light sources, for example, the iBright imager
Shipping Condition Dry Ice
Description The No-Stain Protein Labeling Reagent forms covalent bonds with the lysine amino acid side chains on all proteins
Product Type Protein Labeling Reagent
Run Time 10 minutes
Quantity 1 kit
For Use With (Application) Compatible with all downstream immunodetection steps (blocking, antibody binding, chemiluminescent or fluorescence based detection
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Do the iBright imagers support total protein normalization?

iBright Imaging Systems support total lane protein-based normalization and housekeeping gene (HKP)-based normalization. To support the methods best suited for your experiment, iBright Imaging Systems and iBright Analysis Software provide multiple quantitation and normalization options to monitor or mathematically compensate for experimental or sample variability.

To learn more about total lane protein normalization, explore our application note.

What is the shelf life of the No-Stain Protein Labeling Reagent (Cat. No. A44717, A44449)?

The shelf life of the No-Stain Protein Labeling Reagent is at least 2 years from the date of receipt of the product.

After staining a membrane using the No-Stain Protein Labeling Reagent (Cat. No. A44717), is it possible to store the membrane and detect the protein of interest later?

Even though the No-Stain Protein Labeling Reagent (Cat. No. A44717) is light sensitive, membranes can be kept wet in the dark for at least 3 days with minimal effect on the signal. So, yes, it is possible.

Can I get uniform labeling of proteins when using the No-Stain Protein Labeling Reagent?

Yes, the No-Stain Protein Labeling Reagent provides uniform labeling of proteins in gels or on membranes, provided they are imaged the same way.

Can I get a similar signal intensity from two same-type gels or two same-type membranes that I label using the No-Stain Protein Labeling Reagent?

Yes, reproducible signal intensity will be obtained when using the No-Stain Protein Labeling Reagent to label either the same type, identically loaded gels or the same type membranes from the transfer of identically loaded, same-type gels: quantitation results will be similar between the gel pairs and the membrane pairs.

Are you planning to develop additional data analysis software for the iBright imager?

The iBright imager now has software enabling Total Protein Normalization when using the No-Stain Protein Labeling Reagent. Additional data analysis software for the iBright imager is not being planned at this time.

Can I perform data analysis with the No-Stain Protein Labeling Reagent if I don't have an iBright imager?

You should be able to use the same software that you are currently using for quantitative westerns. If you are measuring the signal intensity of a target protein or a housekeeping protein with software such as ImageJ or OpenLab, then you can use that same software for measuring the intensity of No-Stain Labeling Reagent-labeled protein bands.

How does the No-Stain Protein Labeling Reagent work?

The No-Stain Protein Labeling Reagent provides two active ingredients that result in a fluorophore being covalently attached to the side chains of some of the lysine residues of a protein. One of these active ingredients is contained within the No-Stain Derivatizer and consists of a fluorogenic molecule that does not fluoresce unless it undergoes a specialized reaction with the active ingredient contained within the No-Stain Activator.

Can I use the No-Stain Protein Labeling Reagent with an orange or red dye (i.e., will the signal appear in channel 2, 3, 4 or 5, not just channel 1 in the iBright imager)?

Channels 3, 4 and 5 on the iBright imager can be used for multiplexing without interference while using the No-Stain Protein Labeling Reagent. Channels 1 and 2 on the iBright imager will show interference. Fluorophores for multiplexing that are compatible with the No-Stain Protein Labeling Reagent are listed here, under the “Secondary Abs” tab (https://www.thermofisher.com/us/en/home/life-science/protein-biology/protein-assays-analysis/western-blotting/detect-proteins-western-blot/total-protein-normalization.html).

What are the excitation and emission maxima of the fluorophore used in the No-Stain Protein Labeling Reagent?

The fluorophore’s excitation and emission maxima are ~488 nm and 590 nm, respectively. The fluorophore’s spectra can be accessed here, under the “Secondary Abs” tab (https://www.thermofisher.com/us/en/home/life-science/protein-biology/protein-assays-analysis/western-blotting/detect-proteins-western-blot/total-protein-normalization.html).

Can I use any imager to visualize the signal from proteins labeled using the No-Stain Protein Labeling Reagent?

The No-Stain Protein Labeling Reagent is compatible with a wide-range of imagers that have a UV, Green LED, or fluorescence light source, for example, the iBright imagers.

Can I use the No-Stain Protein Labeling Reagent with any gel type?

Yes, the No-Stain Protein Labeling Reagent can label proteins in any gel type (i.e., precast gels or 'pour your own' gels) and any gel chemistry (i.e., Bis-Tris, Tris-Glycine, Tris-Acetate, and Tricine gels).

Can proteins in a gel be transferred to a membrane after the gel has been labeled using the No-Stain Protein Labeling Reagent?

We do not recommend labeling a gel with No-Stain Protein Labeling Reagent and then using that same gel for transfer. However, proteins on a membrane transferred from an unlabeled gel can be visualized using the No-Stain Protein Labeling Reagent.

Can I use the No-Stain Protein Labeling Reagent to label a gel for visualizing total protein?

Yes, the protocol in the User Guide (https://assets.thermofisher.com/TFS-Assets/LSG/manuals/MAN0018742_NoStain_LabelingReagent_UG.pdf) provides instructions on how to do this.

Will the presence of molecules that are covalently added on the protein through using the No-Stain Protein Labeling Reagent affect the ability of the labeled protein to bind antibody and thus impact the resultant immunodetection signal?

During the development of the No-Stain Protein Labeling Reagent, over 100 different antigen-antibody pairs were evaluated for impact of using the reagent. The binding of some antibodies to labeled antigens appeared to be impacted compared to the binding to corresponding unlabeled antigens. However, a complete loss of immunodetection signal was not observed for any of the labeled antigens tested.

For the affected antibodies, the immunodetection signal was either higher or lower compared to unlabeled antigens. For most cases in which a lower immunodetection signal was observed due to labeling, a slight increase in exposure time during imaging compensated for the reduced signal; when using smart or automatic exposure settings on an imager, this increase in exposure time was self-adjusting, showing that the labeling did not cause a significant impact on the result.


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