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Query: UNIPROT:P47989 (
xanthine oxidase
)
8,633
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Glyceryl trinitrate (GTN) has found widespread use for the treatment of
angina pectoris
, a pathological condition manifested by chest pain resulting from insufficient blood supply to the heart. Metabolic conversion of GTN, a nitric oxide (NO) pro-drug, into NO induces vasodilation and improves blood flow. Patients develop tolerance to GTN after several weeks of continuous use, limiting the potential for long-term therapy. The mechanistic cause of nitrate tolerance is relatively unknown. We developed a cell culture model of nitrate tolerance that utilizes stable isotopes to measure metabolism of
15
N
3
-GTN into
15
N-nitrite. We performed global metabolomics to identify the mechanism of GTN-induced nitrate tolerance and to elucidate the protective role of vitamin C (ascorbic acid). Metabolomics analyses revealed that GTN impaired purine metabolism and depleted intracellular ATP and GTP. GTN inactivated
xanthine oxidase
(XO), an enzyme that is critical for the metabolic bioactivation of GTN into NO. Ascorbic acid prevented inactivation of XO, resulting in increased NO production from GTN. Our studies suggest that ascorbic acid has the ability to prevent nitrate tolerance by protecting XO, but not aldehyde dehydrogenase (another GTN bioactivating enzyme), from GTN-induced inactivation. Our findings provide a mechanistic explanation for the previously observed beneficial effects of ascorbic acid in nitrate therapy.
...
PMID:Metabolomics-Driven Elucidation of Cellular Nitrate Tolerance Reveals Ascorbic Acid Prevents Nitroglycerin-Induced Inactivation of Xanthine Oxidase. 3031 19
Aim To study the oxidative modification of red blood cell Cu,Zn superoxide dismutase (SOD) in patients with ischemic heart disease (IHD) in vivo and in vitro to substantiate the use of a new oxidative stress marker.Material and methods Red blood cell Cu,Zn SOD was measured by depression of nitrotetrazolium blue reduction by the superoxide anion generated in
xanthine oxidase
xanthine oxidation. Red blood cell Cu,Zn SOD was measured immunochemically. The biochemical study was performed in the control group (patients with low extremity fracture without known history of cardiovascular diseases and hyperlipidemia) and in groups of patients with acute myocardial infarction, stable
angina
, and decompensated heart failure. For evaluation of oxidative stress intensity in IHD patients, an empirical SOD oxidative modification coefficient (OMCSOD) was proposed, which is a Cu,Zn SOD activity / Cu,Zn SOD content ratio.Results The red blood cell Cu,Zn SOD activity was significantly decreased in all IHD groups compared to the control group. Furthermore, OMCSOD was also considerably decreased in IHD patients, which warrants the use of this biochemical index as an oxidative stress marker.Conclusion It was shown that the Cu,Zn SOD modification was induced by interaction of the enzyme molecules with a natural dicarbonyl, malonic dialdehyde, and OMCSOD can be used for evaluation of oxidative stress intensity in IHD patients.
...
PMID:[Indicator Characterizing Carbonyl-Dependent Modification of Erythrocytic Superoxydismutase as a Biochemical Marker of Oxidative Stress in Coronary Heart Disease]. 3251 5
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