Proteome-pI 2.0 - Proteome Isoelectric Point Database

Proteome-pI 2.0 is an updated version of an online database (Proteome-pI [http://isoelectricpointdb.org/]) containing the information about predicted isoelectric points. 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 2.0 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 the 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.

Proteome-pI 2.0是在线数据库Proteome-pI（原访问网址：http://isoelectricpointdb.org/）的更新版本，收录了预测等电点（isoelectric point）相关信息。等电点指特定分子净电荷为零时的pH值，是诸多分析生物化学与蛋白质组学技术的核心参数之一，尤其广泛应用于二维凝胶电泳（2D gel electrophoresis，简称2D-PAGE）、毛细管等电聚焦、液相色谱-质谱联用法以及X射线蛋白质晶体学等研究技术。该数据库支持虚拟二维凝胶电泳图谱的检索，同时可基于等电点与分子量定制化生成蛋白质组分级组分。此外，Proteome-pI 2.0可实现多种蛋白质预测方法间的统计对比，还支持对所有生物界内蛋白质等电点分布空间开展生物学探究。数据库内置多项统计工具与交互式浏览、检索、排序功能，支持通过生物体名称、平均等电点、分子量或氨基酸频率进行检索与浏览，极端等电点值的蛋白质数据亦可供获取。针对特定蛋白质组，用户可依据预测方法、等电点范围与分子量范围检索目标蛋白质，该特性可有效缩小二维凝胶电泳凝胶分析或质谱实验前的潜在靶标范围。最后，该数据库还预计算了部分通用统计数据，包括蛋白质总数量、氨基酸总数、平均序列长度、单氨基酸及二氨基酸频率，同时收录了对应于主流蛋白质数据库如UniProtKB/TrEMBL与NCBI非冗余（nr）数据库的数据集。

搜集汇总

背景与挑战

背景概述

Proteome-pI 2.0是一个更新版的在线数据库，专注于预测蛋白质等电点，为2D凝胶电泳等分析技术提供关键参数支持。它提供虚拟2D-PAGE图、基于等电点和分子量的蛋白质组分定制功能，并包含统计比较工具及预计算的通用统计数据，便于用户交互浏览和搜索。