they interact with the acidic group of the iTAGTM dye, causing theformation of an insoluble dye-protein complex that precipitatesout of solution (Amamcharla and Metzger, 2010). This results inthe decrease of the dye in solution, resulting in a lowerspectrophotometer reading. Therefore, the amount of proteinpresent in a sample is relative to the decrease in the spectralabsorbance (Amamcharla and Metzger, 2010).