Proteins have a tendency to aggregate over time and the risk for drugs in the biopharmaceutical industry is that the presence of aggregates will stimulate an immune response. Size-exclusion chromatography (SEC) is a powerful tool that is commonly used to look at the aggregation of proteins.
SEC separates proteins by size, and is commonly used to measure molecular weight and characterize aggregation. By adding a light scattering detector to the system, the molecular weight of the protein monomer, oligomers, and aggregates in a sample can be measured independent of their elution volume. In addition, multi-angle light scattering (MALS) can also be used to measure the radius of gyration (Rg) of large aggregates that scatter light anisotropically.
Materials and Methods
The molecular weight and aggregate content of pepsin was successfully measured using the Viscotek SEC-MALS 20 system, and their amounts quantified. Where the aggregates are large enough, their size (Rg) can also be measured.
(1) Measuring protein aggregation with the Viscotek SEC-MALS 20, Malvern Instruments application note, http://www.malvern.com/MRK1927
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