As complement C3 represented the hotspot for proteolytic processing events, we evaluated the identified C3 N-termini for global abundance in terms of log10-transformed intensities for the CTRL and SLE samples (Fig. 2E) and could identify a very heterogeneous distribution for the N-termini spanning four orders of magnitude from log10 intensities of 3.5–7.6 with a mean log10 intensity of 5.10 in CTRL and 5.04 in SLE (Dataset EV7). This evidence concerns the gene C3 and systemic lupus erythematosus.