protein analysis by liquid phase colorimetry with spectrophotometric readout Bradford protein assay 2013-11-12T17:06:12Z Coomassie dye protein assay JSmith MMO:0000426 The Bradford assay of protein concentration is based on an absorbance shift of the dye Coomassie Brilliant Blue G-250. In the acidic environment of the assay, protein binds to the Coomassie dye, resulting in a shift from reddish/brown to blue in the color of the dye, which can be quantitated by spectrophotometry, i.e., based on the ability of the solution to alter the transmission of light at specific wavelengths in the visible spectrum, that is, to alter the transmission of a specific color of light. The binding of the dye to the protein stabilizes the blue anionic form and the increase of absorbance at 595 nm is proportional to the amount of bound dye, and thus to the amount (concentration) of protein present in the sample. measurement_method_ontology