Abstract
The influence of PEGylation on the thermal stability of small therapeutic proteins was evaluated using two model proteins. Changes in the midpoint of thermal unfolding and the ability to properly refold after thermal denaturation were monitored by differential scanning calorimetry (DSC) as a function of PEGylation and pH. The results showed that PEGylation increased the thermal stability of both model proteins as well as their ability to refold properly after thermal denaturation. The DSC results were compared to traditional accelerated stability data that were collected using size exclusion high performance liquid chromatography (SE-HPLC). The DSC data agreed reasonably well with those from SE-HPLC indicating that microcalorimetry can be an efficient screening tool for PEGylated proteins.
Acknowledgments
The authors would like to thank our colleagues at Adnexus, A Bristol-Myers Squibb R & D Company, for providing CT-322 and its unPEGylated precursor C7, and Peter Ihnat (Biologics Process and Product Development, Bristol-Myers Squibb) for providing the PEGylated and NEM modified dAb samples used for this study. In addition, the authors would also like to thank Lori Burton and Venkatramana Rao for a critical review of the manuscript.
Declaration of interest
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.