Objective To identify ubiquitinated proteins from complex human multiple myeloma (MM) U266 cells,a malignant disorder of differentiated human B cells.Methods Employing a globally proteomic strategy combining of immunoprecipitation,LC-MS/MS and SCX-LC-MS analysis to identified ubiquitination sites,which were identified by detecting signature peptides containing a GG-tag (114.1 Da) and an LRGG-tag (383.2 Da).Results In total,52 ubiquitinated proteins containing 73 ubiquitination sites of which 14 and 59 sites contained LRGG-tag and GG-tag were identified,respectively.Conclusion Classification analysis by of the proteins identified in the study based on the PANTHER showed that they were associated with multiple functional groups.This suggested the involvement of many endogenous proteins in the ubiquitination in MM. Objective To identify ubiquitinated proteins from complex human multiple myeloma (MM) U266 cells, a malignant disorder of differentiated human B cells. Methods Employing a global proteomic strategy combining immunoprecipitation, LC-MS / MS and SCX-LC-MS analysis to identify ubiquitination sites, which were identified by measuring signature peptides containing a GG-tag (114.1 Da) and an LRGG-tag (383.2 Da). Results In total, 52 ubiquitinated proteins containing 73 ubiquitination sites of which 14 and 59 sites contained LRGG-tag and GG-tag were identified, respectively.Conclusion Classification analysis by of the proteins identified in the study based on the PANTHER showed that they were associated with multiple functional groups .his suggested the involvement of many endogenous proteins in the ubiquitination in MM.