Thermo Scientific™

Pierce™ Coomassie Plus (Bradford) Assay Kit

Catalog number: 23236
Thermo Scientific™

Pierce™ Coomassie Plus (Bradford) Assay Kit

Catalog number: 23236
Catalog Number
Unit Size
950 mL
Price (USD)
Price: 238.00
Your Price:
Catalog NumberUnit SizePrice (USD)AvailabilityQuantity
23236950 mL
Price: 238.00
Your Price:
Product Overview
Citations & References
Additional Information
The Pierce Coomassie Plus (Bradford) Protein Assay is a ready-to-use, reducing agent-compatible, improved Bradford assay reagent to quickly measure total protein concentration compared to a protein standard. The Pierce Coomassie Plus Assay Reagent provides increased linearity and half the protein-to-protein variability of other commercial Bradford assay formulations.

Compare all available Bradford assays ›

Features of the Coomassie Plus Protein Assay include:
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
Better—improved linearity and response uniformity compared to traditional Bradford formulations
Flexible—microplate and cuvette protocols provided and adaptable to several target working ranges

The assay is performed at room temperature. Simply add the sample to the tube containing reagent and the resultant blue color is measured at 595 nm following a short room-temperature incubation. The protein assay is compatible with most salts, solvents, buffers, thiols, reducing substances, and metal-chelating agents encountered in protein samples. The assay can be performed in either test tube or microplate format.

How the Coomassie Plus (Bradford) Assay detects protein
Use of Coomassie G-250 dye in a colorimetric reagent for the detection and quantitation of total protein was first described by Dr. Marion Bradford in 1976. In the acidic environment of the reagent, protein binds to the Coomassie dye. This results in a spectral shift from the reddish/brown form of the dye (absorbance maximum at 465 nm) to the blue form of the dye (absorbance maximum at 610 nm). The difference between the two forms of the dye is greatest at 595 nm, so that is the optimal wavelength to measure the blue color from the Coomassie dye-protein complex. If desired, the blue color can be measured at any wavelength between 575 nm and 615 nm. At the two extremes (575 nm and 615 nm) there is a loss of about 10% in the measured amount of color (absorbance) compared to that obtained at 595 nm.

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


Pierce Coomassie Plus (Bradford) Protein Assay Kit
Bradford Assay
Detection Method
Product Line
Product Type
Protein Quantitation Assay
Not Target-Specific
Sufficient For
630 Tube Assays or 3160 Microplate Assays
For Use With (Application)
Solution-based Detection, Absorbance
For Use With (Equipment)
Spectrophotometer, Microplate Reader
950 mL

Contents & Storage

Sufficient For: 630 tube assays or 3160 microplate assays
• Pierce Coomassie Plus Assay Reagent, 950 mL
• Albumin Standard Ampules, 2 mg/mL, 10 x 1 mL

Store Coomassie Plus Assay Reagent at 4°C. Store unopened Albumin Standard Ampules at room temperature.