Method Development for an Easy and Direct Quantitation of Protein Adsorption by Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE)

The current proteomic approach is to identify and analyze proteins of interest, which can potentially be disease biomarkers. However, these important proteins usually exist in very low concentration, making them vulnerable to sample loss by adsorption during any laboratory manipulations. A simple method, sodium dodecyl sulfate polyacrylamide gel electrophoresis coupled with direct protein adsorption analysis (SDS-PAGE/DPA), is presented here for the quantitation of adsorption-caused protein loss. No complicated steps and expensive equipment are involved; this method for protein study enables measurement of proteins adsorbed on vials at extremely low concentrations (in pg/μl). We used this method to characterize the effects of concentration, time, and volume on adsorption. We also applied this method to discover differential sample loss in protein mixtures and its utility in developing preventive strategies of adsorption. This method is further being employed for studying different aspects of adsorption-caused peptide loss.