the goal of this study was to investigate the common clinical chemistry and distribution of xanthine oxidase (xo) in selected tissues of a mouse model of menopause. twenty four nmri female mice were divided into three groups: normal control (nc), and ovariectomized (ovx) groups and an estrogen-treated ovariectomized (ovx+e) group which received subcutaneous injection of estradiol benzoate (2 mg...

1. The catalytic properties of xanthine oxidase in bovine milk (EC 1.2.3.2) are dependent on the state of the enzyme, i.e. whether free or bound to the fat-globule membrane. Oxidase activity of the membrane-bound enzyme towards NADH is enhanced relative to that towards xanthine. This reflects a change in the relative K(m) values and enables the ratio of xanthine to NADH oxidase activities (X/N)...

We previously reported that the all-cis isomer of arachidonic acid, the most naturally occurring isoform of this fatty acid, reduced cuprous copper ion-induced conversion of xanthine dehydrogenase into its reactive oxygen species generating form, xanthine oxidase. In the present study, the effects of all-trans isomer of arachidonic acid, in comparison with cis isomer of arachidonic acid, on the...

the hptlc analysis, antioxidant, and antigout activity of asparagus racemosus, withania somnifera, vitex negundo, plumbago zeylanica, butea monosperma and tephrosia purpurea extracts were investigated. the chemical fingerprinting were carried out by high performance thin layer chromatography (hptlc), antioxidant activity by abts, dpph, frap radical scavenging assays, and antiogout activity by c...

flavonoids could serve as potent inhibitors of xanthine oxidase (xo). in the present study, the effects of ruta graveolens l. extract and its major isolated flavonoids, quercetin and rutin, on guinea pig liver xo have been investigated. the inhibitory effects of r. graveolens, quercetin and its glycoside form, rutin, were assayed spectrophotometrically. r. graveolens extract showed moderate inh...

The corneas of albino rabbits were irradiated (5 min exposure once a day) with UVB rays (312 nm) for 4 days (shorter procedure) or 8 days (longer procedure). The eyes were examined microbiologically and only the corneas of sterile eyes or eyes with non-pathogenic microbes were employed. Histochemically, the activities of reactive oxygen species (ROS)-generating oxidases (xanthine oxidase, D-ami...

T HE ENZYME, XANTHINE OXIDASE, is thought to play a central role in the mobilization of storage iron from the liver.1 In the presence of xanthine oxidase, xanthine is oxidized to uric acid, the enzyme acting as electron acceptor in the oxidation reaction . ‘ Coupled to the oxidation of uric acid is the reduction of ferric ferritin to the ferrous state. The livers of immature rats contain very l...

The structure-activity relationship of flavonoids as inhibitors of xanthine oxidase and as scavengers of the superoxide radical, produced by the action of the enzyme xanthine oxidase, was investigated. The hydroxyl groups at C-5 and C-7 and the double bond between C-2 and C-3 were essential for a high inhibitory activity on xanthine oxidase. Flavones showed slightly higher inhibitory activity t...

Xanthine oxidase is a member of molybdoenzyme family and has catalytic role in purine degradation, metabolizing hypoxanthine and xanthine to uric acid with the generation of superoxides. In the present study, microtitre plate based colorimetric assay was used to screen the xanthine oxidase producing microorganisms from the soil treated with hypoxanthine with different concentrations (2mM, 4mM, ...

Par many years it has been known that purine catabolism in the rat results in the formation and subsequent urinary excretion of allantoin as the main end-product. Individual enzymes catalyzing the steps in purine catabolism have been identified and methods for assaying these enzymes in vitro have been developed. With the discovery that xanthine oxidase activity in vitro is influenced greatly by...