Cell biology and the genome projects a concerted strategy for characterizing multiprotein complexes by using mass spectrometry.

New developments in biological mass spectrometry and the growth of sequence databases are revolutionizing protein analysis. As recent results demonstrate, the high sensitivity and high throughput of this approach allow the rapid characterization of gel-separated proteins and the identification of cognate cDNA and expressed-sequence tag (EST) clones. We advocate here exploiting this new technology for the systematic characterization of multiprotein complexes. The analysis of proteins as components of specific complexes provides an immediate link to biological function and is a powerful method for deciphering the functions of open reading frames uncovered in the genome-sequencing projects.