Since the analysis of plasma proteome necessarily requires a multidimensional approach, it is particularly important to optimize each step, in order to get the best results. Several studies on the efficiency,Etanercept reproducibility and nonspecific binding of different depletion products have been already published. The majority of these studies, however, only assessed HSA or HSA and IgG removal. During the last years, there has been a gradual development of several multiple affinity removal columns for the simultaneous depletion of even more HAPs, able to retain 7, 14 and 20 HAPs. An alternative and innovative strategy to isolate LAPs is based on the treatment of complex protein samples with a large, highly diverse library of hexapeptides bound to a chromatographic support. In theory, each unique hexapeptide binds to a unique protein recognition site. Since HAPs saturate their ligands, exceeding proteins are washed out during the procedure. In contrast, LAPs are concentrated on their specific ligands, thereby decreasing the dynamic range of proteins in the sample. The literature is actually limited in comparing these two major approaches: to the best of our knowledge,Lambrolizumab there are currently only five published papers comparing HAPs depletion and LAPs enrichment, and none of them included the ProteoPrep20 which immunocaptures the highest number of HAPs and therefore should be considered the more efficient currently available depletion system. From the literature, it appears that depletion of only HSA and IgG is less efficient compared to the use of peptide ligand affinity beads. The literature is inconsistent and controversial in the comparison between more complex multi-depletion systems and LAPs enrichment approach. In fact, some authors state that removal of up to 12 and 14 HAPs gives a similar performance as LAPs enrichment, while other authors showed that MARS Hu-7 depletion kit performance surpassed that of ProteoMiner. Many of the above mentioned studies concerning the comparison between different depletion systems or the comparison between depletion and enrichment methods were conducted using 2-DE. The evaluation criterion was based on the number of visualized spots in the gel, without giving information of protein identities.