Protocol for the quantification of protein ng quantities by a Coomassie Brilliant Blue G-250-based hydrophobic assay

Several methods for protein determination have been developed [1] but the ones most commonly used today are based on the reaction of proteins with Commassie Brilliant Blue G-250 (CBB) [2] and alkaline Cu(II) [3]. The most recent modifications of these methods are the Sedmak assay [4] and the bicinchoninic acid (BCA) assay [5]. Another sensitive method for measuring proteins is the colloidal gold protein assay [6] which has been modified to quantify specific proteins of interest [7,8].