A metaproteomic analysis of aspirates of mucosal-luminal interface conducted on pediatric IBD population by Zhang et al. [106] identified ROS and RNS-generating enzymes NOS2, LOX15 (E.C. 1.13.11.33), and dual oxidase 2 (E.C. 1.6.3.1)to be overexpressed in UC, regardless the bowel region from which the samples were harvested (Table 3 and Table S1). Here, NOS2 is linked to irritable bowel syndrome.