Abstract
This article contains data related to the research article entitled "Zipf׳s law in proteomics" (Naryzhny et al., 2017) [1]. The protein composition in the human liver or hepatocarcinoma (HepG2) cells extracts was estimated using a filter-aided sample preparation (FASP) protocol. The protein species/proteoform composition in the human liver was determined by two-dimensional electrophoresis (2-DE) followed by Electrospray Ionization Liquid Chromatography-Tandem Mass Spectrometry (ESI LC-MS/MS). In the case of two-dimensional electrophoresis (2-DE), the gel was stained with Coomassie Brilliant Blue R350, and image analysis was performed with ImageMaster 2D Platinum software (GE Healthcare). The 96 sections in the 2D gel were selected and cut for subsequent ESI LC-MS/MS and protein identification. If the same protein was detected in different sections, it was considered to exist as different protein species/proteoforms. A list of human liver proteoforms detected in this way is presented.