Notes: 1.A rapid and accurate method for the stimation of protein is essential in many fields of protein study.n assay originally deseribed by Bradford has become the preferre method for quantifying protein in many laboratories.This technique is simpler.faster.and more sensitive than the Lowry method.Moreover,when compared with the Lowry method,it is subject to less interference by common reagents and nonprotein components of biological samples. on the Bradford Assa Absorbance at 600 nm Compound Blank Control 0.00 0.26 0.029%sD5 0.003 0.250 0 1%6SDS 0042 0059: 0.1%Triton 0.000 0278 0.051 031E I M 2-Mercaptoethanol 0.00 0.27 1 M Sucrose 0.008 0.261 4 M Urea 0.008 0261 4MNaCl 0.015 0.207: 0014 023% 0.1 M HEPES.PH7.0 0.00 0 0.I M Tris.pH 7.5 0.00 0.261 0.1 M Citrate,pH 5.0 0.015 0.249 10 mM EDTA 0007 0215 1 M (NH4)2504 0.002 026 Data were obtained by mixingofsampewith5ofthe speeified compound efre adding00ofdye "Measurements that differ from the control by more than 0.02 absorbance unit for blank values or more than 10% 2.Binding of protein to Coomassie Blue G250 may shift the absorbance maximum of the blue ionic form of the dye from 590 nm to 620 nm.It might,therefore,appear more sensible to measure the absorbance at the higher wavelength.However.at the usual pH of the assay.an appreciable proportion of the dye is in the green form()which interferes with dye-protein compl 620 nm.Mea 505 represents the best compromise between maximizing the absorbence due to the dye-protein complex while minimizing that due to the green form of the free dye 3.The dye does not bind to free arginine or lysine.or to peptides smaller than about 3000 Da Many peptide hormones and other import bioctive peptides fall into the atter category,and the Bradford assay is not suitable for quantifying the amounts of such compounds