Weiller, GeorgCaraux, GSylvester, N.2015-12-132015-12-131615-9853http://hdl.handle.net/1885/80775Two-dimensional gel electrophoresis, a routine application in proteomics, separates proteins according to their molecular mass (Mr) and isoelectric point (p/). As the genomic sequences for more and more organisms are determined, the Mr and p/ of all their proteins can be estimated computationally. The examination of several of these theoretical proteome plots has revealed a multimodal p/ distribution, however, no conclusive explanation for this unusual distribution has so far been presented. We examined the p/ distribution of 115 fully sequenced genomes and observed that the modal distribution does not reflect phylogeny or sequence evolution, but rather the chemical properties of amino acids. We provide a statistical explanation of why the observed distributions of p/ values are multimodal.Keywords: protein; Arabidopsis; Archaebacterium; article; Caenorhabditis elegans; Drosophila melanogaster; Eubacterium; eukaryote; evolution; genome; isoelectric point; nonhuman; pH; phylogeny; Plasmodium falciparum; priority journal; probability; protein analysis; Extremophiles; Genome; Isoelectric point; Multimodal distribution200410.1002/pmic.2002006482015-12-11