Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.17.3.2 (xanthine oxidase)
 8,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Crosslinking hemoglobin with superoxide dismutase and catalase (PolyHb-SOD-CAT) helps to limit free radical reactivity of modified hemoglobin red blood cell substitutes. In the present study, in vitro oxidant challenge experiments were performed with exogenous hydrogen peroxide (H2O2) and xanthine oxidase-derived superoxide (O2.-). PolyHb-SOD-CAT was compared to PolyHb for the presence of secondary hemoprotein-free radical events. PolyHb-SOD-CAT prevents ferrylhemoglobin formation, measured as Na2S-induced absorbance at 620 nm. Similarly, PolyHb-SOD-CAT inhibited ferrozine-detectable iron release at high oxidant-heme ratios. The formation of oxygen radicals, monitored by salicylate hydroxylation, was prevented at high oxidant-heme ratios with PolyHb-SOD-CAT. The peroxidation of liposomal membranes was also inhibited in PolyHb-SOD-CAT mixtures subject to oxidant challenge. These results show that PolyHb-SOD-CAT prevents secondary hemoprotein-associated free radical events. This new type of modified hemoglobin oxygen carrier with antioxidant activity may reduce the potential toxicity of hemoglobin-based substitutes in certain applications, especially during reperfusion of ischemic tissues.
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PMID:Absence of hemoprotein-associated free radical events following oxidant challenge of crosslinked hemoglobin-superoxide dismutase catalase. 960

In mammals, xanthine oxidase (E.C. 1.17.3.2) catalyzes the hydroxylation of a wide variety of heterocyclic substrates such as purines, pyrimidines, and pterins, in addition to aldehydes [1] as all-trans-retinaldehyde [2-5]. Here, we show that buttermilk xanthine oxidase was capable to oxidizing all-trans-retinol (t-ROL) to all-trans-retinaldehyde (t-RAL) that was successively oxidized to all-trans-retinoic acid (t-RA). A rise in the enzyme activity, when t-ROL-CRBP complex was assayed, with respect to the free t-ROL, was observed. Furthermore, treatment of the enzyme with Na2S and glutathione resulted in a significant increment in catalytic activity toward t-ROL and t-RAL, due to the reconstitution of the native structural organization of the molybdenum centre of molybdopterin cofactor of the desulfo form of xanthine oxidase.
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PMID:Xanthine oxidase catalyzes the oxidation of retinol. 1784 15