Database of pre-computed isoelectric points and molecular weights for proteins and digest peptides from model organism proteomes (20,115 species)
The goals of the database include making statistical comparisons of the various prediction methods (21 algorithms implemented) as well as facilitating the biological investigation of protein isoelectric point space. The isoelectric point, the pH at which a particular molecule carries no net electrical charge, is an 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 analysis
identification of proteins in the sample and limiting the complexity of the further analysis
Protease digests (peptides with molecular weight and isoelectric point) can be
useful for bottom-up proteomics MS analysis
Proteomes in silico digested with the five most frequently used proteases (Trypsin, Chymotrypsin, Trypsin+LysC, LysN, ArgC)
For pKa vaules of individual proteomes go to the given proteome subpage.
useful for bottom-up proteomics MS analysis
61,329,034 protein sequences from 20,115 proteomes with isoelectric point predicted using 21 algorithms
5.38 Billion dissociation constant (pKa) predictions for proteins
Proteomes in silico digested with the five most frequently used proteases (Trypsin, Chymotrypsin, Trypsin+LysC, LysN, ArgC)
In total, 9.58 Billion peptides
Check some of the most frequently used proteomes
| Homo sapiens (100,100 proteins) |
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| Mus musculus (63,656 proteins) |
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| Arabidopsis thaliana (41,612 proteins) |
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| Drosophila melanogaster (23,524 proteins) |
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| Danio rerio (47,088 proteins) |
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| Xenopus tropicalis (46,313 proteins) |
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| Caenorhabditis elegans (28,314 proteins) |
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| Escherichia coli (4,450 proteins) |
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| Bacillus subtilis (4,267 proteins) |
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| Mycobacterium tuberculosis (3,993 proteins) |
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| Salmonella enterica (5,880 proteins) |
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| Vibrio cholerae (3,782 proteins) |
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| Helicobacter pylori (1,552 proteins) |
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| HIV (9 proteins) |
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| Bacteriophage lambda (66 proteins) |
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| T4 phage (278 proteins) |
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| Herpes simplex virus 1 (77 proteins) |
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| SARS-CoV (15 proteins) |
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| SARS-CoV-2 (17 proteins) |
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| SARS coronavirus WH20 (10 proteins) |
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| Bat SARS-like coronavirus WIV1 (13 proteins) |
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If you are interested in the analysis of isoelectric point for proteins coming from all organisms use one of the files
| PDB (601k protein chains) |
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| Swiss-Prot (561k proteins) |
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| UniProtKB/TrEMBL (219M proteins) |
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| nr (409M proteins) |
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| the lowest pI fraction (250k proteins) |
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| the highest pI fraction (250k proteins) |
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Proteome-pI provides also pKa calculation for individual proteins
| PDB 601k protein chains 39.5 mln pKa values |
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| Swiss-Prot 561k proteins 48.4 mln pKa values |
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For pKa vaules of individual proteomes go to the given proteome subpage.
Proteome-pI 2.0 is available under Creative Commons Attribution-NoDerivs license, for more details see here
Funding: National Science Centre, Poland [2018/29/B/NZ2/01403]
Funding: National Science Centre, Poland [2018/29/B/NZ2/01403]
| Reference: Kozlowski LP. Proteome-pI 2.0: Proteome Isoelectric Point Database Update. Nucleic Acids Res. 2021, doi: 10.1093/nar/gkab944 | Contact: Lukasz P. Kozlowski |