SOD1 and type 1 diabetes mellitus: Not surprisingly, several enzymes responsible for forming, repairing and/or regulating PTMs such as peptidylarginine deiminase (PADs), antioxidant enzymes, catalase, glutathione peroxidase 1 (GPx1), and superoxide dismutase (SOD) are also found to modulate T1D autoimmunity and glucose and insulin metabolism.