by Philip Chapman, Protein Purification Specialist, Bio-Rad Laboratories, Co-authored by Katie Schaefer, Protein Purification Specialist, Bio-Rad Laboratories
Conventional downstream processing for protein purification begins with a protein capture step, commonly using a Protein A resin, followed by two or more polishing steps to remove product- and process-related impurities. Although Protein A resins demonstrate high specificity and affinity, there are several limitations associated with their use, such as the cost — using Protein A resins can account for over 50% of the entire process. Additionally, they are unable to differentiate between functional and aggregated proteins, which may impact purified sample quality during the acidic elution step. These issues are often heightened by low protein expression, pH sensitivity, and limited stability.
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