BSA Monomer-Dimer Elucidation with the BI-MwA

Aggregation kills. Aggregated therapeutic proteins can provoke immune response and have reduced therapeutic effect. This has led to regulatory and industrial interest in identifying aggregates for elimination. Size-exclusion chromatography (SEC/GPC) has been a useful technique for the determination of molecular weights of proteins. However, its usefulness is limited by the requirement for calibration of the SEC/GPC columns with "standards comprising proteins of known molecular weight but which may not be of the same chemistry as the unknown protein. Then depending on the eluent it is possible that certain proteins might adhere to the stationary phase during elution, yielding erroneous molecular weight determinations. A better approach is to equip the SEC/GPCsystem with a light scattering detector, enabling accurate molecular weight determinations without the need for column calibration. In this application note, we illustrate the power of this method by confirming the presence of monomeric and dimeric species of bovine serum albumin (BSA) under standard chromatography conditions.