Proteomics is the large-scale, systematic study of the entire complement of proteins (proteome) expressed by a genome, cell, tissue, or organism at a given time and under specific conditions. Techniques include 2D-gel electrophoresis, mass spectrometry (MALDI-TOF, ESI-MS), and protein microarrays. Metabolomics studies small-molecule metabolites; genomics studies the genome; bioinformatics provides the computational tools.