AAT Bioquest

Bradford Protein Assay Calculator

The Bradford Protein Assay is a one-step, nearly instantaneous analytical procedure used to measure the concentration of protein in a solution. It is a colorimetric protein assay based on an absorbance shift of Coomassie Brilliant Blue G-250 from red to blue, the degree to which is proportional to protein concentration. The Bradford Protein Assay has an advantage over direct absorbance measurements, such as using OD280, in that it is less susceptible to interference by various chemical compounds like carbohydrates.

As with most colorimetric or fluorimetric assay, the Bradford Protein Assay requires the generation of a standard curve to calculate the unknown concentration of protein in a solution. The standard curve is created by measuring the absorbances of a known set of protein standards, which are either provided by the manufacturer of the assay or can be easily generated through serial dilution of a stock solution. Include link to serial dilution calculator here. A best fit regression model is applied to the protein standards and their respective response values. This regression model can then be used to calculate the concentration of any unknown protein sample.

This tool will generate a curvi-linear regression model for any given experimental data set with which to determine an unknown protein concentration for the Bradford Protein Assay.

How to use this tool

1. Paste experimental data into the box on the right. Data can be copied directly from Excel columns. Data can also be comma-separated, tab-separated or space-separated values. If entering data manually, only enter one X-Value per line.

Replicates can be graphed simultaneously. Graph will generate error bars based on the standard error of the mean (SEM). Simply paste or enter all data columns to begin. Format should be as follows:

ConcentrationResponse 1Response 2...

Users can graph up to three data sets on the same graph for comparison purposes. To add a new data set , press the "+" tab above the data entry area.Data sets can be renamed by double clicking the tab. Each dataset will generate a corresponding Polynomial value as well as the equation for the best fit line.

2. Verify your data is accurate in the table that appears.

3. Press the "Calculate Polynomial" button to display results, including calculations and graph.

Data Entry

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Process data


Have a question or a feature request about this tool? Feel free to reach out to us and let us know! We're always looking for ways to improve!

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This online tool may be cited as follows


"Quest Graph™ Bradford Protein Assay Calculator." AAT Bioquest, Inc.19 Apr2024https://www.aatbio.com/tools/bradford-protein-assay-calculator.


AAT Bioquest, Inc. (2024April 19). Quest Graph™ Bradford Protein Assay Calculator. AAT Bioquest. https://www.aatbio.com/tools/bradford-protein-assay-calculator.