Creative Proteomics services

Proteomics Service - Top Down Proteomics

Peptidomics Services

Top-down mass spectrometry, as an emerging approach for characterization of intact proteins, is established as a contrast to the bottom-up strategy, which is also called shotgun method, for analysis of peptides from enzymatic or chemical cleavage of intact proteins. Currently the bottom-up strategy is the most mature and most widely used approach for protein identification, characterization of post-translational modifications, and even relative and absolute quantification. But meanwhile, the application of the bottom-up strategy is limited by its inherent shortages.

Top-Down based Sequencing Services

In top-down proteomics, intact protein molecular ions generated by ESI or MALDI are introduced into mass analyzer and are subjected to gas-phase fragmentation. Top-down analysis facilitates direct observation of C- and N-termini for identification of truncations and distinguish one isoform from the other by different sequences.

Top Down-based Characterization Services of PTMs

Top-Down MS is powerful for comprehensive analysis of protein modifications because Top-Down MS is able to analyze intact proteins/peptides without proteolysis. Therefore, the strategy can preserve the labile modified motifs which are mostly lost when shotgun method is applied and CID is used for fragmentation in analysis of protein therapeutics, such as monoclonal antibodies and recombinant proteins.

Characterization Services of Protein Structure

The application of Bottom-Up strategy is limited by incomplete or ambiguous characterization of alternative splice forms, diverse modifications and endogenous protein cleavages. As an alternative, the Top-Down strategy has been utilized more with the advancement of analytical instruments. Except for FT-ICR mass spectrometer, invention and innovation of orbitrap mass spectrometer has promote the development of top-down proteomics.