Fig. 1.

Formation of HO^· radicals as part of the homeostasis of reactive oxygen species in pancreatic beta cells. This figure depicts the different pathways of hydrogen (H₂O₂) generation in the different subcellular organelles, with H₂O₂ either originating from the superoxide radical in the cytosol and in the mitochondria or directly during proinsulin-folding in the endoplasmic reticulum (ER). The figure provides no quantitative information on the amounts of H₂O₂ formation in the different subcellular compartments