title: Oxidation of reduced cucumber ascorbate oxidase.
abstract: Reoxidation process of reduced cucumber ascorbate oxidase (1.10.3.3) with dioxygen was investigated in detail through absorption, circular dichroic (CD) and electron paramagnetic resonance (EPR) spectra. One of the three type I coppers and the type II copper were reoxidized more rapidly than other type I coppers. The principal active site of ascorbate oxidase was considered to be comprised of one type I, one type II and a pair of type III coppers similarly to the active sites in laccase and ceruloplasmin. Remaining two type I and a pair of type III coppers were also disclosed to contribute to the oxidation of L-ascorbate.
mesh_terms: D001204:Ascorbate Oxidase / Q000378:metabolism*; D001665:Binding Sites; D002942:Circular Dichroism; D003300:Copper; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D010100:Oxygen; D010944:Plants / Q000201:enzymology*; D013053:Spectrophotometry; D014675:Vegetables
chemical_list: D003300:Copper; D010088:Oxidoreductases; D001204:Ascorbate Oxidase; D010100:Oxygen