Mass spectrometry-based proteomics and medical research

Proteomics is the study of all proteins expressed in a particular cell type, tissue or organism, and the changes in their relative abundance as the cell, tissue or organism develops, ages, or is subjected to any stimulus or insult, as for example in the case of neuronal stimulation or disease. Recently, this discipline has acquired significance in biological and health sciences due to advances in other related areas that have facilitated the identification and quantification of individual proteins in complex mixtures. Among these technical and scientific achievements are:

  1. The availability of large databases containing the complete genome of many species, included our own
  2. The availability of powerful computers and computer algorithms to interrogate those databases using a variety of tools
  3. The possibility of generating ions in the gas phase of very large molecules such as proteins and DNA
  4. The use of new mass spectrometers than can measure their masses with a high degree of accuracy, resolution and reproducibility and finally
  5. The introduction and adaptation of new and well-established chemistries and purification procedures as well as their integration with operational workflows with mass spectrometers.

The KU Med MSPC is a state-of-the-art research facility that provides technical services for researchers throughout the entire Kansas City area.  The facility began operation in 2004 and has progressively established a range of instrumentations and methodologies.  The various experimental approaches require the use of different types of mass spectrometers. Mass measurements of peptides and proteins are done in the gas phase and the main ionization methods used in our Facility are Matrix assisted laser desorption ionization (MALDI) and electrospray ionization (ESI)

MALDI. In MALDI, molecules are sublimated from a crystalline matrix by the use of a pulsed laser. In ESI, the ions originate from a liquid solution to which a high voltage is applied.  MALDI is particularly useful in identifying components of relatively simple protein mixtures, such as those present as spots on 2D-PAGE.

ESI. More complex protein mixtures are analyzed by a combination of liquid chromatography connected online to an ESI mass spectrometer.  ESI instruments generally fragment the ions produced by a technique called collision induced dissociation (CID).  Because the fragmentation pattern of any given peptide ion is predictable, it is possible to deduce the amino acid sequence of a particular peptide ion through analyzing its CID mass spectrum.  ESI mass spectrometers utilize a variety of ion detectors, the most sensitive and highest mass accuracy are ion resonance Fourier Transform mass spectrometers. 

In addition to mass spectrometry, our MSPC facility also offers a variety of complementary instrumentation for proteomics research.  A Typhoon gel scanner is available for sensitive protein detection using a variety of fluorescent dyes.  Sample throughput is enhanced by the availability of an automatic gel slicer and digestor and an automatic MALDI spotter.

Last modified: Mar 26, 2013