Access to data file has been altered to "Closed" as the dataset has been hosted elsewhere. New DOI to be added (AA 17/07/2024) Liquid chromatography-mass spectrometry data to accompany manuscript entitled "SUMO4 promotes SUMO deconjugation required for DNA double-strand break repair" by Garvin et al. 2023. The file contains raw data from SUMO4 IP with the U2OS cells and U2OS-SUMO4 knock-out clones. The file also contains the search results performed with Sequest HT search engine within Proteomme Discoverer.