The entire complement of proteins, protein-protein interactions and post-translational modifications within an organism is known as its proteome; the moniker being a blend of protein and genome. Since protein modifications, such as phosphorylation, acetylation, glycosylation and methylation, are state-dependent, the proteome is constantly changing in response to cellular cues. Proteome-focused studies, then, must specify the conditions under which the proteome was analyzed. Proteomics is the study of the proteome. Like genomics, proteomics is a branch of bioanalysis that provides valuable data about a cell. Unlike genomics, in which data can be gathered from any cell of an organism, proteomics relies on cell specific, temporal and environment specific readouts.
Modern proteomics benefits from the ability to assess the modification state of proteins directly, using a combination of techniques such as mass spectrometry, western blotting and enrichment. The proteome of a cell is of much greater complexity than the genome.