We identified GR and SUMO2/3 chromatomes in B-cell acute leukemia cells (NALM6) and studied the impact of SUMOylation inhibition (SUMOi) on them utilizing small molecule inhibitor ML792. Chromatome members were identified with Rapid Immunoprecipitation Mass spectrometry of Endogenous proteins (RIME) in absence and presence of the synthetic glucocorticoid dexamethasone (Dex) and ML792. Mass spectrometry analyses were executed with high resolution mass spectrometry (LC-MS), using the Evosep One liquid chromatography system coupled to a hybrid trapped ion mobility quadrupole TOF mass spectrometer (Bruker timsTOF Pro) via a CaptiveSpray nano-electrospray ion source. Chromatome members were discriminated from background based on spectral count expression filtering and intensity ratio compared to corresponding IgG control sample.