| 11. | Xanthine dehydrogenase can be converted to xanthine oxidase by reversible sulfhydryl oxidation or by irreversible proteolytic modification.
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| 12. | Enzymes that contain the molybdopterin cofactor include xanthine oxidase, DMSO reductase, sulfite oxidase, and nitrate reductase.
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| 13. | Xanthine oxidase loses its function and gains ascorbase function when some of the iron atoms in XO are replaced with copper atoms.
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| 14. | Type I xanthinuria has been traced directly to mutations of the " XDH " gene which mediates xanthine oxidase activity.
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| 15. | Both xanthine oxidase and xanthine oxidoreductase are also present in corneal epithelium and endothelium and may be involved in oxidative eye injury.
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| 16. | Models for hemerythrin, an enzyme with a diiron active site, and xanthine oxidase, a molybdoenzyme, have been examined.
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| 17. | In a 24-hour urine excretion of more than 800 mg, which indicates overproduction, a xanthine oxidase inhibitor is preferred.
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| 18. | Hypoxanthine is then oxidatively catabolized first to xanthine and then to uric acid, and the reaction is catalyzed by the enzyme xanthine oxidase:
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| 19. | A 24-hour urine excretion of more than 800 mg, which indicates overproduction, is an indication for a xanthine oxidase inhibitor.
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| 20. | Because xanthine oxidase is a metabolic pathway for uric acid formation, the xanthine oxidase inhibitor allopurinol is used in the treatment of gout.
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