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Published on: March 29, 2018
Physical instability, aggregation and conformational changes of recombinant human bone morphogenetic protein-2
Ludmila Luca1, Martinus A H Capelle, Gia Machaidze
1Department of Pharmaceutics and Biopharmaceutics, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, CH-1211 Geneva 4, Switzerland.
International Journal of Pharmaceutics
|February 17, 2010
Summary
The physical stability of recombinant human bone morphogenetic protein-2 (rhBMP-2) is significantly affected by pH. Higher pH (6.5) leads to increased aggregation and conformational changes compared to lower pH (4.5).
Area of Science:
- Biochemistry
- Materials Science
- Protein Engineering
Background:
- Recombinant human bone morphogenetic protein-2 (rhBMP-2) is crucial for bone regeneration.
- Understanding rhBMP-2's physical stability is vital for effective therapeutic delivery systems.
- Protein aggregation can significantly impact biological activity and stability.
Purpose of the Study:
- To investigate the influence of pH on the physical stability of rhBMP-2 in aqueous solutions.
- To characterize conformational changes and aggregation states of rhBMP-2 at different pH values.
- To provide insights for optimizing rhBMP-2 formulation and delivery.
Main Methods:
- Intrinsic and extrinsic fluorescence spectroscopy (Nile Red, 1,8-ANS) were used to assess protein conformation.
- 90-degree light-scattering measured particle size and aggregation.
- Transmission electron microscopy (TEM) visualized protein aggregate morphology and size distribution.
Main Results:
- rhBMP-2 at pH 6.5 exhibited altered fluorescence properties (intensity, lifetime) compared to pH 4.5.
- Increased light-scattering intensity at pH 6.5 indicated greater aggregation.
- TEM revealed larger and more numerous rhBMP-2 aggregates at pH 6.5 (0.1-2 microm) versus pH 4.5 (approx. 100 nm).
Conclusions:
- pH significantly impacts rhBMP-2's physical stability, inducing conformational changes and promoting aggregation at higher pH.
- rhBMP-2 is more stable and less aggregated at pH 4.5 than at pH 6.5.
- These findings are critical for designing stable and effective rhBMP-2 delivery systems.
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