NAR Molecular Biology Database Collection entry number 1989
Kozlowski, Lukasz
Quantitative and Computational Biology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Lower Saxony, 37077, Germany

Database Description

Proteome-pI is an online database containing information about predicted isoelectric points for 5,029 proteomes (21 million of sequences) calculated using 18 methods.
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, liquid chromatography–mass spectrometry and X-ray protein crystallography.
The database allows the retrieval of virtual 2D-PAGE plots and the development of customized fractions of proteome based on isoelectric point and molecular weight. Moreover, Proteome-pI facilitates statistical comparisons of the various prediction methods as well as biological investigation of protein isoelectric point space in all kingdoms of life (
The database includes various statistics and tools for interactive browsing, searching and sorting. It can be searched and browsed by organism name, average isoelectric point, molecular weight or amino acid frequencies. Proteins with extreme pI values are also available. For individual proteomes, users can retrieve proteins of interest given the method, isoelectric point and molecular weight ranges (this particular feature can be highly useful to limit potential targets in analysis of 2DPAGE gels or before conducting mass spectrometry). Finally, some general statistics (total number of proteins, amino acids, average sequence length, amino acid and di-amino acid frequencies) and datasets corresponding to major protein databases such as UniProtKB/TrEMBL and the NCBI non-redundant (nr) database have also been precalculated.

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