Site-specific proteomics data of SUMO-SUMO branched peptides. Related to Fig. 6, F–H. (A) Column charts of average intensity values for the branched peptides diagnostic of SUMO-SUMO linkages via the indicated sites. Error bars show SEM. Number of purifications, n = 4. (B)t test summary for the two-tailed pairwise comparisons indicated for each SUMO1 (upper) or SUMO2/3 (lower) modifications to any SUMO. Welch’s correction was applied for heteroskedastic data. Red entries are P < 0.05. The number of different peptides used for each site is indicated (evidence count).