Co-localization of manganese superoxide dismutase and NADH diaphorase

Manganese superoxide dismutase (Mn SOD), mitochondrial enzyme, defends against the toxic effects of superoxide radical (O2.-) in pathological processes by catalyzing the conversion of O2.- to hydrogen peroxide (H2O2). The activity of another enzyme, NADH diaphorase, forms the basis for a histochemical method used commonly to demonstrate nerve cell bodies in the enteric plexuses. We found identical patterns of localization of Mn SOD immunoreactivity and NADH diaphorase activity in brain, esophagus, stomach, colon, liver, and kidney. NADH diaphorase enzymatic activity co-migrated with complexes of Mn SOD on a non-denaturing gel. This suggests that the NADH diaphorase may in some way be related to Mn SOD.