Figure 2: The benefit of using multiple exclusion MS runs. Venn diagram of the peptides identified in the first iTRAQ experiment. The no-exclusion run identified 324 distinct peptides. Of these 128 were identified in the first exclusion run together with 74 novel peptides. The second exclusion run produced 38 additional novel peptides that had not been identified in the no-exclusion or in the first exclusion MS runs.