Show Order Info
SKU AR0145
Product name Coomassie (Bradford) Protein Assay Kit(for 100-1500 μg/ml protein)
Form Solution (liquid)
Applications Western blotting, ELISA, immunofluorescence; protein expression assays, protein profiling and characterization; protein quantitation assays

List of Components

DescriptionQuantityVolumeContentsCatalog Number
Coomassie (Bradford) Protein Assay Reagent1100mLcontaining coomassie G-250 dye, methanol, phosphoric acid and solubilizing agents in water
Caution: Phosphoric acid is a corrosive liquid.
AR0145-1
BSA Standard120mL (2mg/mL)containing bovine serum albumin (BSA) at a concentration of 2mg/mL in a solution of 0.9% saline and 0.05% sodium azideAR0145-2

Overview

Form Supplied Coomassie (Bradford) Protein Assay Reagent: ready-to-use 1X solution
BSA Standard: stock solution for preparing a series of standard protein dilutions
Assays per kit Tube procedure: 100 assays
Microplate procedure: 400 assays
Storage Upon receipt store at 4°C. It is stable at 4°C for one year.
Assay Range 100 - 1500μg/mL
Equivalent Thermofisher (Product No. 23200), Assay Range: 100 - 1500μg/mL
Bio-Rad (Product No. 5000002), Assay Range: 200 - 1400μg/mL
Physical State Brown-red liquid
Reagent Absorbance A470 nm (brown-red)
Reagent-Protein complex Absorbance A595 nm (blue)
Activity Max activity in acidic conditions
Reagent Type Protein assay kit; Western Blotting related
Usage To be used with: Non-detergent extracted protein samples from cell lysates
Description Coomassie (Bradford) Protein Assay Kit is a ready-to-use, reducing agent compatible, total protein analysis reagent used for the quick determination of total protein concentration by measuring A595 and comparing to a protein standard concentration-vs.-absorption curve according to Bradford.
Cite This Product Coomassie (Bradford) Protein Assay Kit (Boster Biological Technology, Pleasanton CA, USA, Catalog # AR0145)
Application Western blotting, ELISA, immunofluorescence; protein expression assays, protein profiling and characterization; protein quantitation assays
*Our Boster Guarantee covers the use of this product in the above tested applications.
Precautions FOR RESEARCH USE ONLY. NOT FOR DIAGNOSTIC AND CLINICAL USE
Compatibility with reagents Incompatible with RIPA lysis buffer and other detergent-containing lysis and extraction buffers *

*Note: Elevated concentrations of detergent interfere with the assay. SDS interferes by either binding strongly with the protein (at low concentrations), thus inhibiting the protein binding sites for the dye reagent and causing underestimations of protein concentration in solution, or by associating strongly with the green form of the Coomassie dye, causing the equilibrium to shift towards the blue form, thus increasing the absorbance at 595 nm independent of protein presence. In this case the BCA Protein Assay Kit or Micro BCA Protein Assay Kit should be used.

Assay Principle

Coomassie (Bradford) Protein Assay Kit is a ready-to-use, reducing agent compatible, total protein analysis reagent used for the quick determination of total protein concentration by measuring A595 and comparing to a protein standard concentration-vs.-absorption curve according to Bradford.

Background

The Coomassie (Bradford) protein assay kit is a quick coomassie - binding, colorimetric method for total protein quantitation based on the Bradford protein assay. When the Coomassie dye binds to protein in an acidic medium, an immediate shift in absorption maximum occurs from 465 nm to 595 nm with a concomitant color change of the solution from brown to blue. The spectrophotometric measurement of the intensity of this resulting blue color (the absorbance at 595 nm) is used to determine the concentration of protein in solutions. Protein concentrations are estimated by reference to absorbances obtained for a series of standard protein dilutions, which are assayed alongside the unknown sample.
The different colors of the coomassie dye are a result of the different charged states of the dye molecule. The blue dye molecule is an anion with an overall charge of -1. The development of color in coomassie dye-based (Bradford) protein assays has been associated with stabilizing the negatively charged state of the dye molecule by binding to certain basic / positively charged amino acids (primarily arginine, lysine and histidine) in the protein, even under acid conditions when most of the molecules in solution are in the cationic form. Van der Waals forces and hydrophobic interactions also participate in the formation of dye- protein complexes. The number of Coomassie dye ligands bound to each protein molecule is approximately proportional to the number of positive charges found on the protein. The amount of the complex present in solution is a measure for the protein concentration, and can be estimated by use of an absorbance reading. The increase of absorbance at 595 nm is proportional to the intensity of the blue of the solution, thus to the amount of bound dye, and thus to the amount (concentration) of protein present in the sample. 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 kit.

Assay Procedure

Test Tube Procedure (Test Range = 25-1,500 μg/ml)

1. Add 20 μl of each standard and unknown samples into separate labeled test tubes.

2. Add 1 ml of Coomassie (Bradford) Protein Assay Reagent to each tube and mix well.

3. Incubate samples at room temperature for 10 minutes.

4. Set the wavelength of spectrophotometer at 595 nm. Calibrate the instrument to zero. Subsequently, measure the absorbance of all samples.

5. Subtract OD595 of Blank from all readings.

6. Plot the BSA standard curve: OD595 (on Y axis) vs BSA Standard concentration (on X axis). Use the standard curve to determine the protein concentration of each unknown sample.

Microplate Procedure (Test Range = 25-1,500 μg/ml)

1. Add 5 μl of each standard and unknown samples into separate microplate wells.

2. Add 250 μl of the Coomassie (Bradford) Protein Assay Reagent to each well and mix thoroughly on plate shaker for 30 seconds.

3. Incubate samples at room temperature for 10 minutes.

4. Measure the absorbance at 595 nm on a plate reader.

5. Subtract OD595 of Blank from all readings.

6. Plot the BSA standard curve: OD595 (on Y axis) vs BSA Standard concentration (on X axis). Use the standard curve to determine the protein concentration of each unknown sample.

Coomassie (Bradford) Protein Assay Kit Images

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Coomassie (Bradford) Protein Assay Kit
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50 mL per pack, Solution (liquid)
Coomassie (Bradford) Protein Assay Kit
Standard curve for Coomassie Plus Protein Assay Kit (AR0145)
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Publications

Costunolide and dehydrocostuslactone combination treatment inhibit breast cancer by inducing cell cycle arrest and apoptosis through c-Myc/p53 and AKT/14-3-3 pathway
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Synthesized Multiple Antigenic Polypeptide Vaccine Based on B-Cell Epitopes of Human Heparanase Could Elicit a Potent Antimetastatic Effect on Human Hepatocellular Carcinoma?In Vivo
Peng Z, Wang Y, Fan J, Lin X, Liu C, Xu Y, Ji W, Yan C, Su C. Sci Rep. 2017 Jan 24;7:41254. doi: 10.1038/srep41254. Costunolide and dehydrocostuslactone combination treatment inhibit breast cancer by inducing cell cycle arrest and apoptosis through c-Myc/p53 and AKT/14-3-3 pathway