Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:1.16.3.1 (
ceruloplasmin
)
5,074
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The O2-utilizing (type O, oxidase) form of
xanthine oxidoreductase
is primarily responsible for its
ferroxidase
activity. This form of
xanthine oxidoreductase
has 1000 times the
ferroxidase
activity of the serum
ferroxidase
caeruloplasmin
. It has the ability to catalyse the oxidative incorporation of iron into transferrin at very low Fe2+ and O2 concentrations. Furthermore, the pH optimum of the
ferroxidase
activity of the enzyme is compatible with the conditions of pH that normally exist in the intestinal mucosa, where it has been proposed that
xanthine oxidoreductase
may facilitate the absorption of ionic iron. Modification of the molybdenum (Mb) centres of the enzyme in vitro by treatment with cyanide, methanol or allopurinol completely abolishes its
ferroxidase
activity. The feeding of dietary tungsten to rats, which prevents the incorporation of molybdenum into newly synthesized intestinal
xanthine oxidoreductase
, results in the progressive loss of the
ferroxidase
activity of intestinal-mucosa homogenates. Removal of the flavin centres from the enzyme also results in the complete loss of
ferroxidase
activity; however, the
ferroxidase
activity of the flavin-free form of the enzyme can be restored with artificial electron acceptors that interact with the molybdenum or non-haem iron centres. The presence of superoxide dismutase or catalase in the assay system results in little inhibition of the
ferroxidase
activity of
xanthine oxidoreductase
.
...
PMID:Studies of the ferroxidase activity of native and chemically modified xanthine oxidoreductase. 375 93
