The Protein Man's Blog | A Discussion of Protein Research

The Bradford assay is a fast and efficient colorimetric assay to determine the protein concentration in a wide range of solutions and is widely used for protein content of cell fractions and protein concentrations for gel electrophoresis. It is often done before an SDS-PAGE analysis. Using the reagent Coomassie Brilliant Blue G-250, the solution undergoes a visible change in color when the dye binds to proteins via van de Waals and electrostatic interactions, causing a shift from a dark red to a deep blue. This is a result of stabilization moving the absorbance maximum of the dye from 470 to 595 nm. Tested samples typically take less than five minutes to reach the indicative measures of 595 nm absorbance concentration, making the Bradford assay both reliable and quick.

When conducting an experiment, it is essential to choose the correct protein assay.

Protein assays are one of the most widely used scientific methods, particularly in life sciences. An assay is an efficient spectroscopic procedure that analyzes the concentration of protein in a solution, also referred to as protein concentration quantitation. Being able to measure this concentration is an integral part of any laboratory workflow involving protein extraction, purification, labeling, or analysis. It is necessary for an array of research, including processing protein samples for isolation, separation, and analysis by chromatographic, electrophoretic, and immunochemical techniques. There are different types of assays and each can be useful for different applications, but many assays work in similar ways and utilize standards.