title: Involvement of superoxide in the catalytic cycle of diamine oxidase.
abstract: The reaction of pig kidney diamine oxidase (amine:oxygen oxidoreductase (deaminating) (pyridoxal-containing), EC 1.4.3.6) could be significantly inhibited by superoxide dismutase active copper chelates but not by native 2Cu,2Zn-superoxide dimutase (cuprein). The ligands alone as well as Cd2+, a heavy metal of similar toxicity to Cu2+, showed no inhibition whatsoever. This indicates that .O-2 participates in the catalytic cycle and is produced at a site scarcely accessible to such a large molecule as cuprein. A mechanism for the second, aerobic step of the diamine oxidase reaction is suggested.
mesh_terms: D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D003300:Copper / Q000494:pharmacology; D007668:Kidney / Q000201:enzymology; D010100:Oxygen / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*; D013552:Swine
chemical_list: D013481:Superoxides; D003300:Copper; D013482:Superoxide Dismutase; D006631:Amine Oxidase (Copper-Containing); D010100:Oxygen