In connection with studiesrelated to the purines in serum of leukemia patients (1), xanthine interference was observed in the Kodak Ektachem enzymically based determination of uric acid, leading to significant underestimation of the latter’s actual concentration-a finding that agrees with a previous report (2). In hereditary xanthinuria, total oxypurine concentrations in serum ranged from 1 to ...

In 1948 Miller (1) demonstrated that the loss of liver xanthine oxidase activity in the rat greatly exceeded the loss of liver protein during acute inanition. Moreover, xanthine oxidase appeared to be the most labile of the four liver enzymes studied. Westerfeld and Richert (2) observed that increasing the level of protein in the diet tended to bring about an increase in liver xanthine oxidase ...

The aim of this study is to comprehensively assess the change in oxidoreductive enzyme activities, due potential catalyzing oxidation and reduction reactions, as basic processes on undrained drained peat soils. On peatlands, a significant decrease activities was observed such xanthine oxidase, urate phenol peroxidase with an increase depth. It connected significantly higher porosity values, hot...

BACKGROUND The effect of reactive oxygen species (ROS) on platelet function in coronary heart disease (CHD) is complex and poorly defined. Platelet aggregation studies in healthy volunteers have demonstrated contrasting results when platelets are exposed to ROS. We investigated the effect of ROS on whole blood aggregation (WBA) and the endothelial cell-platelet interaction in patients with CHD....

The reductive metabolism of 2-nitrofluorene, a carcinogenic air pollutant, in rat skin microsomes and cytosol was investigated. 2-Nitrofluorene was reduced to the corresponding amine by the microsomes with NADPH and by the cytosol with 2-hydroxypyrimidine or 4-hydroxypyrimidine under anaerobic conditions. The cytosolic activity was much higher than that of skin microsomes. The 2- or 4-hydroxypy...

Heart failure is a clinical syndrome associated with elevated levels of oxygen-derived free radicals. Xanthine oxidase activity is believed to be one source of reactive oxygen species in the failing heart. Interventions designed to reduce oxidative stress are believed to have significant therapeutic potential in heart failure. This study tested the hypothesis that xanthine oxidase activity woul...

In vitro assembly or complementation of a hybrid assimilatory nitrate reductase was attained by mixing a preparation of nitrate-induced N. crassa mutant nit-1 specifically with acid-treated (pH 2.5) bovine milk or intestinal xanthine oxidase, rabbit liver aldehyde oxidase, or chicken liver xanthine dehydrogenase. The complementation reaction specifically required induced nit-1, the only nitrate...

Chemistry and Biochemistry of Flavoenzymes (Muller, F., ed.), vol. 111, pp. 309-317, CRC Press, Boca Raton 7 Ratti, S., Curti, B., Zanetti, G. and Galli, E. (1985) J. Bacteriol. 163, 724-729 8 Vanoni, M. A., Negri, A., Zanetti, G., Ronchi, S. and Curti, B. (1990) Biochem. Biophys. Acta 1039, 374-377 9 Vanoni, M. A., Nuzzi, L., Rescigno, M., Zanetti, G. and Curti, B. (1991) Eur. J. Biochem. 202,...