
Protein Characterization
Our team employs a customized approach to ensure successful generation of high-quality proteins with robust lot-to-lot reproducibility. Characterization is integrated throughout each project, rather than postponed until the end. This enables rapid orthogonal evaluation of critical protein-related key parameters. New assays are continuously implemented, and existing ones are adapted to meeting the specific needs of each application.
Orthogonal evaluation of related key parameters:
- Purity - N-term/C-term homogeneity, chemical stability, post-translational modifications, residual protease identification
- Size in solution - Oligomerization state, aggregation susceptibility, resistance to stress
- Stability and folding - Low and high order structure, thermodynamic evaluation, forced degradation study
- Sequence integrity - N-term/C-term homogeneity, chemical stability, post-translational modifications
- Biomolecular interaction - Rate of association/disassociation
Characterization and analytical methods
Protein concentration
- Colorimetric (Bradford/Lowry/BCA/RCDC)
- Spectrophotometric: absorbance at 280nm
Aggregation and sizing
- SEC-HPLC / SEC-MALS
- Analytical ultracentrifugation (SV-AUC)
- Dynamic light scattering (DLS)
- SDS-PAGE
- Glutaraldehyde crosslinking
Reactivity
- ELISA
Purity
- Analytical SEC-HPLC
- Capillary electrophoresis
- SDS-PAGE/ densitometry
Identity
- Western blot
- Peptide mapping (LC-MS/MS)
- Dynamic light scattering
Secondary / tertiary structure
- Circular dichroism (far/near UV CD)
- UV/Vis absorbance spectroscopy
- Intrinsic fluorescence
- Differential scanning fluorimetry and calorimetry
- Transmission electron microscopy
- N-glycan analysis
Intact molecular weight
- SEC-MALS (multi-angle light scattering)
- LC-MS
Process related impurities
- Residual proteins; residual DNA (qPCR)
- Enotoxins (LAL)
- Sterility
Protein activity
- Protein binding affinity (Bio-layer interferometry)
- Enzymatic/colorimetric assays
- Capillary electrophoresis
- SDS-PAGE/ densitometry
Thermal stability
- Differential scanning fluorimetry (DSF) and calorimetry (DSC)
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