Disaggregation of High-Molecular Weight Species During Downstream Processing to Recover Functional Monomer

The use of chaotropic agents to recover functional monomeric material was investigated for the downstream purification of an Fe-fusion protein containing high levels of high-molecular weight (HMW) species. In batch studies, chaotropic agents irreversibly disaggregated a majority of the aggregated protein. An integrated processing mode, termed as on-column disaggregation, was developed in which the protein was captured on Protein A chromatography and then a chaotropic agent was used to simultaneously elute the bound protein and disaggregate the HMW species. On-column disaggregation process resulted in protein recoveries of >95% and aggregation reduction of similar to 50%. Analytical results are presented showing that the recovered monomeric material was comparable to the reference protein in biochemical, biophysical, and pharmacokinetic properties. The kinetic and molecular mechanisms governing protein aggregation and disaggregation will also be elucidated. For the Pc-fusion protein studied here, incorporation of the disaggregation strategy in both batch and on-column modes led to an increase of >10% in overall downstream yield. (C) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 26: 717-726, 2010