Proteome-pI - Proteome Isoelectric Point Database http://isoelectricpointdb.org
The database of pre-computed isoelectric points for proteomes from different model organisms (5029 species).
Goals of the database include making statistical comparisons of the various prediction methods (18 algorithms implemented) as well as facilitating biological investigation of protein isoelectric point space. Isoelectric point, the pH at which a particular molecule carries no net electrical charge, is important parameter for many analytical biochemistry and proteomics techniques, especially for 2D gel electrophoresis (2D-PAGE), capillary isoelectric focusing (cIEF), liquid chromatography–mass spectrometry (LC-MS) and X-ray protein crystallography
2D plots of predicted molecular weight and isoelectric point can be useful for initial identification of proteins in the sample and limiting the complexity of the further analyses
The database contains the data for 21,721,250 sequences from 5,029 proteomes with isoelectric point predicted using 18 algorithms.
Additionally, in 'Download" section you can obtain isoelectric points for all major protein databases (UniProt, nr, PDB).
Proteome-pI example report for Salmonella enterica
At the top, the average isoelectric point, precalculated fractions of proteins according to isoelectric point and virtual 2D-PAGE plot for the proteome are shown. In the next section, the user can retrieve a subset of proteins within specified isoelectric point and molecular weight ranges calculated using a particular method. Next, proteins with minimal and maximal isoelectric points are presented along with some general statistics.