Protein Characterization

Many samples require an extra step to identify possible post-translational modifications, whether it is a form of enrichment, or intact mass, or a combination of a few techniques, we will work with you to help you achieve your research goals.



The Core is equipped to analyze and has mapped acetylation, citrulation, S-nitrosation, O-GlcNAclyation, phosphorylation, proline hydroxylation and ubiquitination sites. Techniques used to determine modification and amino acid modified are customized to each project. Cost estimates given after discussing options with client.


Enrichment Techniques

The Core routinely uses  a variety of enrichment techniques to  including to enrich for phosphorylated petides (from in-gel or in-solution, relative quantitation is available). 


High Resolution Mass Analysis of Proteins  

The Core offers a LCMS method to accurately measure a protein’s mass of up to 90 kDa to within 100 ppm (or 10 Da). The method requires <1 ug (or 10 pmol) per protein and was developed 1) to detect the presence and stoichiometry of protein modifications by comparing the measured mass to the calculated mass; 2) to detect and quantify the proteins in a functional complex; and 3) to determine cleavage sites if the N- or C-terminus is known. 




The Johns Hopkins Mass Spectrometry and Proteomic Facility

725 N. Wolfe Street
Wood Basic Science Building, Room 504
Baltimore, MD 21205