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
Protease digests (peptides with molecular weight and isoelectric point) can be
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) |
Mus musculus (63,656 proteins) |
Arabidopsis thaliana (41,612 proteins) |
Drosophila melanogaster (23,524 proteins) |
Danio rerio (47,088 proteins) |
Xenopus tropicalis (46,313 proteins) |
Caenorhabditis elegans (28,314 proteins) |
Escherichia coli (4,450 proteins) |
Bacillus subtilis (4,267 proteins) |
Mycobacterium tuberculosis (3,993 proteins) |
Salmonella enterica (5,880 proteins) |
Vibrio cholerae (3,782 proteins) |
Helicobacter pylori (1,552 proteins) |
Bacteriophage lambda (66 proteins) |
Herpes simplex virus 1 (77 proteins) |
SARS coronavirus WH20 (10 proteins) |
Bat SARS-like coronavirus WIV1 (13 proteins) |
If you are interested in the analysis of isoelectric point for proteins coming from all organisms use one of the files
Swiss-Prot (561k proteins) |
UniProtKB/TrEMBL (219M proteins) |
the lowest pI fraction (250k proteins) |
the highest pI fraction (250k proteins) |