Proteomics and Mass Spectrometry
Proteomics, a growing field of biochemical research, attempts to catalog and characterize proteins expressed by genes, compare variations in their expression levels under different conditions (notably sickness versus health), study their interactions, and identify their functional roles. Proteomics, in a sense, is more complex than genomics, not only because there are so many possible interactions among proteins, but because there are so many more proteins than genes. Although, the humane genome project has identified more than 30,000 genes, the proteins encoded by these genes amount to more than half million.
During the past two decades, mass spectrometry has become established as the primary method for protein identification from complex mixtures of biological origin. This is largely attributable to advances in ionization techniques and instrumentation that allow routine analysis of minute amounts (typically femtomoles) of nonvolatile, polar compounds such as peptides and proteins.
In our laboratory, we are interested in characterizing proteins and their post-translational modifications by liquid chromatography/mass spectrometry (LC/MS).
Currently, we are involved in a collaborative project with Professor Jon Friesen to identify the phosophorlyation sites in the enzyme CTP:phosphocholine cytidylyltransferase (CT), Phosphorlyation is important because it is a major control mechanism for the regulation of diverse cellular processes.
Our approach to this problem is to digest the protein into smaller peptides using a suitable enzyme. The peptides are then separated by HPLC and their molecular weight determined by MS. The addition of a phosphate group can then be determined.
In addition to the instrumentation at Illinois State University, we are making use of the sophisticated mass spectrometric facilities at the University of California, San Francisco to help us in this research.