Proteome-pI - Proteome Isoelectric Point Database

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

21,721,250 sequences from 5,029 proteomes with isoelectric point predicted using 18 algorithms

Check some of the most frequently used proteomes

Homo sapiens
(92179 proteins)
Mus musculus
(58774 proteins)
Arabidopsis thaliana
(33445 proteins)
Drosophila melanogaster
(23296 proteins)
Danio rerio
(43309 proteins)
Xenopus tropicalis
(23598 proteins)
Caenorhabditis elegans
(27799 proteins)

Escherichia coli
(4314 proteins)
Bacillus subtilis
(4205 proteins)
Mycobacterium tuberculosis
(4050 proteins)
Salmonella enterica
(5128 proteins)
Vibrio cholerae
(3784 proteins)
Helicobacter pylori
(1553 proteins)

Phage lambda
(68 proteins)
T4 phage
(278 proteins)
Herpes simplex virus 1
(77 proteins)

If you are interested in the analysis of isoelectric point for proteins coming from all organisms use one of the files

(339k proteins)
(550k proteins)
(63M proteins)
(86M proteins)

the lowest pI fraction
(10k proteins)
the highest pI fraction
(10k proteins)

Proteome-pI is available only for non-commercial and academic users, for details see license

Reference: Kozlowski LP. Proteome-pI: proteome isoelectric point database. Nucleic Acids Res. 2016. doi: 10.1093/nar/gkw978       Contact: Lukasz P. Kozlowski