Difference Between Bradford and Lowry Protein Assay | Bradford vs Lowry Protein Assay

The key difference between bradford and lowry protein assay is that Bradford protein assay is based on the absorbance shift of the dye Coomassie brilliant blue G-250 while Lowry protein assay is based on the reaction of copper ions (Cu+) ions produced by the oxidation of peptide bonds with Folin–Ciocalteu reagent.

An assay is an analytical technique that helps to characterize the major functional components of a sample. Hence, an assay could be either a qualitative or quantitative test. Many fields including laboratory medicine, pharmacology, environmental biology, molecular biology, biochemistry, and immunology use this kind of assays routinely. Bradford and Lowry protein assay are two biochemical assays that determine the protein concentration in a sample solution. Both assays use colorimetric techniques to provide results.


1. Overview and Key Difference
2. What is Bradford Protein Assay
3. What is Lowry Protein Assay
4. Similarities Between Bradford and Lowry Protein Assay
5. Side by Side Comparison – Bradford vs Lowry Protein Assay in Tabular Form
6. Summary

What is Bradford Protein Assay?

Bradford protein assay is a rapid spectroscopic analytical procedure for protein analysis. It shows high accuracy when measuring the protein concentration in a solution. Marion Bradford introduced this procedure in 1976. In this assay, the total reaction is based on the amino acid composition of the proteins measured. In other terms, Bradford protein assay is a colorimetric assay. It uses the dye Coomassie brilliant blue. Hence, this colorimetric protein assay depends on the absorbance shift of the dye. Coomassie brilliant blue G-250 exists in three formats: cationic (red), anionic (blue) and neutral (green). During acidic conditions, the red form of the dye gets converted to blue. It confirms the binding of the protein. If the protein is not present, the solution may remain in brown color.