DETERMINATION OF BACTERIAL PROTEIN PROFILES BY MATRIX-ASSISTED LASER DESORPTION IONIZATION MASS-SPECTROMETRY WITH HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY/

A rapid method for profiling bacterial and cellular proteins has been developed using a combination of capillary high-performance liquid chr omatography separation followed by (MALDI-MS) matrix-assisted laser de sorption/ionization mass spectrometric analysis. In this method, bacte ria are sonicated, the cell walls broken, and the water-soluble protei ns precipitated for analysis. The proteins are separated by capillary liquid chromatography and detected on-line by a UV absorption detector . The eluents are then collected for off-line analysis by MALDI-MS. Us ing this method, it is demonstrated that bacteria can be discriminated based upon their protein profiles to the species level with only pmol level detection of proteins. It has also proved to be a fast and accu rate means for monitoring the expression of Hsp27 in an insect cell sy stem.