This protein assay, based on the method of Bradford, is a simple and accurate procedure for determining protein concentration. The Bradford Assay is a dye-binding assay in which a differential color change of a dye occurs in response to various concentrations of protein. The absorbance maximum for an acidic solution of Coomassie Brilliant Blue G-250 dye shifts from 465 nm to 595 nm when binding to protein. The Coomassie blue dye binds to primarily basic and aromatic amino acid residues, especially arginine. Protein extraction and sample dilution buffer are included in the kit to avoid interactions with buffer and detergent components. The diluted, ready-to-use BSA standards are also included with the kit.