The Protein Assay kit, based on Bradford method, is a fast, simple and accurate procedure for determining the concentration of soluble proteins. The principle of the assay involves a differential color change of an acidic dye occurs at 595 nm when the dye is added to protein solution. The measurement could be achieved conveniently by using a regular spectrophotometer or microplate reader. When compared with a standard curve, it provides a relative measurement of protein concentration.