To directly test AMPP2 function, five independent insertion lines distributed along the At3g05350 gene map were characterized. Among them, four (ampp2-1/ampp2-2/ampp2-3/ampp2-4) behave as true KO lines as they show no detectable full-length AMPP2 transcript while ampp2-5 behaves as WT. In this experiment, N-terminomics profiling was achieved across all lines (4 KO, ampp2-5) and compared to the parental WT line, Col-0.