Protein Characterisation

Detailed protein characterization already at early stages of a drug development is a prerequisite to ensure the integrity and consistency of the drug substance used for clinical and commercial applications.

For characterization of your recombinant protein, monoclonal antibody or vaccine TOPLAB offers a set of analytical tools:


  Analysis of protein identity

o  Confirmation of correct N-terminus by Edman degradation

o  Confirmation of full length expression by PMF  

o  Exact determination of amino acid sequence by

-  Nano-LC-ESI-MS/MS

De novo sequencing (Edman)

o  Western blot with product specific antibodies

o  IEF gel in comparison to a standard sample

o  HPLC in comparison to a standard sample


Analysis of protein integrity

o  Mass determination by nano-LC-ESI-MS/MS

o  Post-translational modifications – peptide mapping and XICs analysis

-  Disulfide bridges and free sulfhydryl group assignment by comparison of peptide maps under non-reducing and reducing conditions

-  Glycosylation site determination by comparison of glycosylated and deglycosylated cleaved protein

-  Glycan analysis

-  Deamidation site determination and relative quantification of deamidation status by LC-ESI-MS/MS

-  Oxidation site deamidation and relative quantification of oxidation status by LC-ESI-MS/MS


Determination of protein purity

o  1D SDS PAGE and 2D PAGE to resolve all components of a sample

o  PMF and database searches against host cell organism

o  Nano-LC-ESI-MS/MS and emPAI for rough quantification of sample components

o  Relative quantification of impurities by Isotope coded Protein label (ICPL)

o  Determination of protein fragments and isoforms by 2D DIGE

o  Absolute quantification by MRM (targeted approach)