23200-Coomassie-Prot-Assay-250

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. Both the Coomassie (Bradford) Protein Assay Kit and the Coomassie Plus (Bradford) Assay Kit are modifications of the reagent first reported by Dr. Bradford.

Coomassie dye-binding assays are a fast and easy way to perform protein assays. The assay is performed at room temperature and no special equipment is required. Briefly, for either the Coomassie (Bradford) Protein Assay or the Coomassie Plus Protein Assay, the sample is added to the tube containing reagent and the resultant blue color is measured at 595 nm following a short room-temperature incubation. The Coomassie dye-containing protein assays are compatible with most salts, solvents, buffers, thiols, reducing substances, and metal chelating agents encountered in protein samples.

Protocol summaries

Step 1 Step 2 Notes
Combine 0.05 mL sample + 1.5 mL Coomassie Reagent, mix well Read at 595 nm
  • Total assay time: 80 minutes
  • Simple, fast protocol
  • One reagent system, stable for 12 months
  • Ready-to-use formulation
  • Nearly immediate color development at room temperature
  • Color response sensitive to changes in pH
  • Temperature-dependence of color response
  • Low-odor formulation
Step 1 Step 2 Notes
Combine 0.03 mL sample + 1.5 mL Coomassie Reagent, mix well Read at 595 nm
  • Total assay time: 80 minutes
  • Simple, fast protocol
  • One reagent system, stable for 12 months
  • Ready-to-use formulation
  • Nearly immediate color development at room temperature
  • Color response sensitive to changes in pH
  • Temperature-dependence of color response

Assay overviews

  • Coomassie Plus (Bradford) Protein Assay—brown-to-blue (A595 nm), fast, ready-to-use, reducing agent–compatible assay reagent to measure total protein concentration vs. protein standard.
  • Coomassie (Bradford) Protein Assay—brown-to-blue (A595 nm), ready-to-use, classic reducing agent–compatible assay reagent to measure total protein concentration vs. protein standard.
Each assay has its own advantages. Please use the table and information below to help select the best protein assay for your application.
Product Coomassie Plus (Bradford) Protein Assay Coomassie (Bradford) Protein Assay
Linear color response

✓*

 
Cuvette assay range 100 to 1,500
1 to 25
100 to 1,500
1 to 25
Microplate assay range 100 to 1,500
1 to 25
100 to 1,500
1 to 25
Compatibilities Most reducing agents; chelators Most reducing agents; chelators
Incompatibilities Detergents Detergents
Product size 950 mL/kit 950 mL/kit
Catalog # Order Now Order Now
* Linear color response in the Plus assay, but less linear color response in the standard assay.