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Updated: Jul 3, 2026
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Ensemble Force Spectroscopy by Shear Forces
Published on: July 26, 2022
Effect of high shear on proteins.
1Department of Pharmaceutical Research and Development, Genentech, Inc., 460 Point San Bruno Boulevard, South San Francisco, California 94080.
Biotechnology and Bioengineering
|August 20, 1996
Summary
High shear forces in bioprocessing did not significantly impact protein aggregation. However, high shear did cause conformational changes and peptide bond breakage in recombinant human growth hormone (rhGH).
Area of Science:
- Biotechnology
- Protein Chemistry
- Biophysical Chemistry
Background:
- High shear forces are common in bioprocessing, particularly during agitation and emulsification.
- Understanding the impact of shear on protein stability is crucial for biopharmaceutical manufacturing.
Purpose of the Study:
- To investigate the effects of high shear and high shear rate on protein structure and stability.
- To compare the stability of two model proteins, recombinant human growth hormone (rhGH) and recombinant human deoxyribonuclease (rhDNase), under high shear conditions.
Main Methods:
- Utilized two concentric cylinder-based shear systems: a closed concentric-cylinder shear device (CCSD) and a rotor/stator homogenizer.
- Calculated shear rate and shear using mathematical modeling.
- Assessed protein aggregation, conformational changes (using scanning microcalorimetry), and fragmentation (using SDS-PAGE).
Main Results:
- Neither high shear nor high shear rate significantly affected protein aggregation for either rhGH or rhDNase.
- Highly sheared rhGH exhibited a lower melting temperature and enthalpy, indicating conformational changes.
- SDS-PAGE revealed low molecular-weight fragments in sheared rhGH, suggesting peptide bond breakage.
- rhDNase demonstrated greater stability, with no observed conformational changes or fragmentation under high shear.
Conclusions:
- High shear forces can induce conformational changes and fragmentation in susceptible proteins like rhGH, despite not causing aggregation.
- Protein stability varies, as demonstrated by the relative robustness of rhDNase compared to rhGH under high shear stress.
- These findings have implications for optimizing bioprocessing conditions to minimize protein degradation.
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