The product quality of recombinant proteins is of major importance for their intended purpose. The initial characterization of both simple and complex products should be performed as soon as practical. However, to comply with this high standard, appropriate selection of complementary methods is required. Therefore, conventional and sophisticated techniques are available, providing diverse information about the product quality.In this chapter methods are presented, which enable the determination of the overall protein quality, their aggregation and peptide composition. Methods applied for the determination of posttranslational modifications such as glycan analysis are not described. In this regard, chromatographic, high-resolution technologies for the integrity of proteins as well as Western blot with specific detection methods are introduced, and individual strengths and perceived limitations are highlighted.
Keywords: Charge variations; Electrophoresis; Peptide map; Protein quality; Size exclusion chromatography; Western blot.