Top Down, Middle Out, and Bottom Up: Mass Spectrometry in Biomedical Research

Classic proteomic workflows analyze tryptic peptides, which generally weigh less than 3000 Da, using a "bottom up" approach. The importance of multiple and coordinated post-translational modifications compels the analysis of longer peptides (using "middle out" analysis) and intact proteins (using "top down" analysis). Professor Catherine Fenselau of the Department of Chemistry and Biochemistry at the University of Maryland is a leading researcher in this field, and has won numerous awards for her work, the most recent of which is the 2014 Eastern Analytical Symposium Award for Outstanding Achievements in Mass Spectrometry. She recently spoke to us about her research with mass spectrometry based analyses of proteins associated with cells known to be an obstacle to anticancer immunotherapies.