The SKCCC Mass Spectrometry Core identifies and quantifies proteins that change expression in well characterized protein fractions from cancerous cells or tissues. This includes identifying and quantifying changes in binding partners and post-translational modifications. Column chromatography and gel electrophoresis based one and two dimensional separations of protein complexes coupled to mass spectrometry are used. Techniques such as difference gel electrophoresis (DIGE), isobaric tag for relative and absolute quantitation (iTRAQ) and 18O-labeling as well as non-labeling methods (MudPit, multi-dimensional protein identification technology) are available for quantifying relative differences in protein expression and post-translational modifications. Also available are Core developed methods to detect post-translational modifications such as LCMS methods to accurately determine the intact mass of proteins, selective fluorescent labeling of S-nitrosothiols (S-FLOS) to detect nitrosated cysteines in proteins, and ion mapping methods to map post-translational modifications that produce a signature mass or mass difference when the modified peptide is fragmented. This Core is a part of larger institutional resource and provides a senior staff mass spectrometrist to assist Center investigators and their staff in preparing and analyzing their samples. Through this senior staff member, the center investigators has access to all the staff and expertise in the Johns Hopkins School of Medicine Mass Spectrometry and Proteomics Core.
Robert N. Cole, Ph.D., Resource Director