Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P47989 (xanthine oxidase)
 8,633 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients with familial adenomatous polyposis (FAP) and age and sex matched controls were tested for cytochrome P4501A2 (CYP1A2), N-acetyltransferase, and xanthine oxidase activities using caffeine urinary metabolites as a discriminator. FAP patients showed significant underactivity of N-acetyltransferase (which inactivates some carcinogens) and significant overactivity of CYP1A2 (which activates some carcinogens). Xanthine oxidase activity, which can generate free radicals and cause cellular damage, was significantly increased in the FAP patients. All but one of the FAP patients had undergone colectomy. A separate group of six patients was therefore assessed before and at an average time of eight weeks after colectomy. No effect on enzyme activity was seen. The differences in enzyme activities detected in this study could produce an excess of active carcinogenic metabolites in the bile of FAP patients and contribute to the high risk for intestinal cancer in FAP.
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PMID:Caffeine phenotyping of cytochrome P4501A2, N-acetyltransferase, and xanthine oxidase in patients with familial adenomatous polyposis. 856 46

The prooxidant/antioxidant imbalance in familial adenomatous polyposis (FAP) is suggested by (i) the intimate connection between APC and prostaglandin H synthase-2 genes, (ii) the increase of the free radical-generating enzyme xanthine oxidase, and (iii) the decrease of antioxidant defences. In this research work we evaluated lipid peroxidation measuring the thiobarbituric acid (TBA) reactive products and we studied the activities of superoxide dismutase (SOD) and catalase as well as the levels of ascorbate and tocopherols in the peripheral blood cells from a total of 27 FAP patients and 83 normal controls. TBA-reactive products were determined according to a previously published method. SOD and catalase activities were determined by the spectrophotometric monitoring of the inhibition of pyrogallol autoxidation and the hydrogen peroxide decomposition rate, respectively. Ascorbate levels were determined by a modified 2,4-dinitrophenylhydrazine method and tocopherol levels by a modified Emmerie-Engle method. The levels of TBA-reactive products were higher in FAP patients than in normal controls. Although no statistically significant differences in SOD and catalase activities were observed between FAP patients and normal controls, we found that ascorbate and tocopherol levels were significantly lower in FAP patients than in normal controls, as assessed by the Mann-Whitney test. Hence, this finding of an imbalance in the prooxidant/antioxidant status may contribute towards new strategies for prevention and therapy in FAP patients.
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PMID:Oxidative stress in familial adenomatous polyposis. 1049 5