Pierce™ Bradford Protein Assay Kit
Please note the name of Cat. No. 23200 has changed from "Pierce Coomassie (Bradford) Protein Assay Kit" to "Pierce Bradford Protein Assay Kit". This update is a name change only, no other changes were made to this product.
Pierce™ Bradford Protein Assay Kit
Thermo Scientific™

Pierce™ Bradford Protein Assay Kit

The Pierce Bradford Protein Assay Kit is a ready-to-use, stable formulation of the traditional Bradford assay reagent for measurement ofRead more
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Catalog number 23200
Price (USD)
155.00
Each
Add to cart
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Price (USD)
155.00
Each
Add to cart
The Pierce Bradford Protein Assay Kit is a ready-to-use, stable formulation of the traditional Bradford assay reagent for measurement of total protein concentration compared to a protein standard. The kit includes Bradford Protein Assay Reagent and a package of Albumin Standard ampules.

Compare all available Bradford assays ›

The Pierce Bradford Protein Assay Kit is a ready-to-use formulation of the popular assay reagent originally described by Bradford in 1976. When mixed with a protein solution, the acidic Coomassie-dye reagent changes color from brown to blue in proportion to the amount of protein present in the sample. Protein determinations are made by comparison to the color response of protein assay standards, usually prepared as a series of known dilutions of bovine serum albumin (BSA) or bovine gamma globulin (BGG). The simple procedure is adaptable to nearly any volume scale, including test tubes, cuvettes, and microplates. The protein assay is compatible with most salts, solvents, buffers, thiols, reducing substances, and metal chelating agents encountered in protein samples.

Features of the Bradford Protein Assay Kit include:
Bradford reagent—stable, ready-to-use kit of the classical Bradford assay reagent
Colorimetric—measure with a standard spectrophotometer or plate reader at 595 nm
Easy to use—single reagent; no working reagent preparation required
Fast—almost immediate color development; add, mix, and read results
Assay range—detects protein concentration in the range 1 to 1500 μg/mL
Flexible—microplate and cuvette protocols provided and adaptable to several target working ranges

How the Bradford Assay detects protein
Development of color in Coomassie dye-based (Bradford) protein assays has been associated with the presence of certain basic amino acids (primarily arginine, lysine, and histidine) in the protein. Van der Waals forces and hydrophobic interactions also participate in the binding of the dye by protein. The number of Coomassie dye ligands bound to each protein molecule is approximately proportional to the number of positive charges found on the protein. Free amino acids, peptides, and low molecular weight proteins do not produce color with Coomassie dye reagents. In general, the mass of a peptide or protein must be at least 3,000 daltons to be assayed with this reagent.

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WARNING: Reproductive Harm - www.P65Warnings.ca.gov
For Research Use Only. Not for use in diagnostic procedures.
Specifications
AssayBradford Assay
Detection MethodColorimetric
Product LinePierce™
Product TypeProtein Quantitation Assay
SpecificityNot Target-Specific
Sufficient For630 Tube Assays or 3800 Microplate Assays
For Use With (Application)Solution-based Detection, Absorbance
For Use With (Equipment)Spectrophotometer, Microplate Reader
Quantity950 mL
Unit SizeEach
Contents & Storage
Sufficient For:
  • 630 tube assays or 3800 microplate assays
  • Pierce Bradford Assay Reagent, 950 mL
  • Albumin Standard ampules, 2 mg/mL, 10 x 1 mL
Store Bradford Protein Assay Reagent at 4°C. Store unopened Albumin Standard ampules at room temperature.

Frequently asked questions (FAQs)

Can you provide the shelf-life for the Pierce Bradford Protein Assay Kit?

The Pierce Bradford Protein Assay Kit is covered under our general 1-year warranty and is guaranteed to be fully functional for 12 months from the date of shipment, if stored as recommended. Please see section 8.1 of our Terms & Conditions of Sale (https://www.thermofisher.com/content/dam/LifeTech/Documents/PDFs/Terms-and-Conditions-of-Sale.pdf) for more details.

Find additional tips, troubleshooting help, and resources within our Protein Assays and Analysis Support Center.

Can I purchase the Pierce Bradford Protein Assay Reagent from the Pierce Bradford Protein Assay Kit as a stand-alone product?

Sorry, the Pierce Bradford Protein Assay Reagent is only available as a component of the Pierce Bradford Protein Assay Kit.

Find additional tips, troubleshooting help, and resources within our Protein Purification and Isolation Support Center.

I assayed two protein samples, each containing a different mixture of proteins of same concentration and observed very different color responses in the assay. What is the cause?

Each of the commonly used total protein assay methods exhibits some degree of varying response toward different proteins. These differences relate to amino acid sequence, pI, structure and the presence of certain side chains or prosthetic groups that can dramatically alter the protein’s color response. Most protein assay methods use BSA or immunoglobulin (IgG) as the standard against which the concentration of protein in the sample is determined. However, if great accuracy is required, prepare the standard curve from a pure sample of the target protein.

Find additional tips, troubleshooting help, and resources within our Protein Assays and Analysis Support Center.

My buffer or components of my buffer are not listed in the compatibility table for my protein assay. What should I do?

You can test the tolerance of the assay for your specific buffer formulation. For in-house generated compatibility information, substances were considered compatible at the indicated concentration in the Standard Test Tube Protocol (found in the manual for each protein assay) if the error in protein concentration estimation caused by the presence of the substance was less than or equal to 10%. The substances were tested using WR prepared immediately before each experiment. Blank-corrected 562nm absorbance measurements (for a 1000µg/mL BSA standard + substance) were compared to the net 562nm measurements of the same standard prepared in 0.9% saline.

Find additional tips, troubleshooting help, and resources within our Protein Assays and Analysis Support Center.

All the components of my sample buffer are at or below the indicated compatible concentration for my protein assay, but I am still seeing too much/too little color development. What could be the problem?

It is possible to have a substance additive affect such that even though a single component is present at a concentration below its listed compatibility, a sample buffer containing a combination of substances could interfere with the assay. You should take steps to eliminate or minimize the effects of the interfering substance(s) by diluting or removing the substance.

Find additional tips, troubleshooting help, and resources within our Protein Assays and Analysis Support Center.