ID   1.17.3.2
DE   Xanthine oxidase.
AN   Hypoxanthine oxidase.
AN   Hypoxanthine-xanthine oxidase.
AN   Hypoxanthine:oxygen oxidoreductase.
AN   Schardinger enzyme.
AN   Xanthine oxidoreductase.
AN   Xanthine:O(2) oxidoreductase.
AN   Xanthine:xanthine oxidase.
CA   Xanthine + H(2)O + O(2) = urate + H(2)O(2).
CF   FAD; Iron-sulfur; Molybdopterin.
CC   -!- Also oxidizes hypoxanthine, some other purines and pterins,
CC       and aldehydes (i.e. possesses the activity of EC 1.2.3.1).
CC   -!- Under some conditions the product is mainly superoxide rather than
CC       peroxide: R-H + H(2)O + 2 O(2) = ROH + 2 O(2)(.-) + 2 H(+).
CC   -!- The enzyme from animal tissues can be converted into EC 1.17.1.4.
CC   -!- That from liver exists in vivo mainly as the dehydrogenase form,
CC       but can be converted into the oxidase form by storage at -20 degrees
CC       Celsius, by treatment with proteolytic enzymes or with organic
CC       solvents, or by thiol reagents such as Cu(2+), N-ethylmaleamide or
CC       4-mercuribenzoate.
CC   -!- The effect of thiol reagents can be reversed by thiols such as 1,4-
CC       dithioerythritol.
CC   -!- EC 1.17.1.4 can also be converted into this enzyme by EC 1.8.4.7 in
CC       the presence of glutathione disulfide.
CC   -!- The Micrococcus enzyme can use ferredoxin as acceptor.
CC   -!- Formerly EC 1.1.3.22 and EC 1.2.3.2.
PR   PROSITE; PDOC00484;
DR   P80457, XDH_BOVIN  ;  P47990, XDH_CHICK  ;  Q9MYW6, XDH_FELCA  ;
DR   P47989, XDH_HUMAN  ;  Q00519, XDH_MOUSE  ;  P22985, XDH_RAT    ;
//