Intermediate dehydrogenase oxidase form of xanthine
oxidoreductase in rat liver.
Uric acid a breakdown product in ingested and endogenously synthesised purines, DNA and RNA are degraded into purine nucleotides and bases, which are then metabolised, via the action of xanthine
oxidase, to xanthine
and then uric acid .
The XO activities with xanthine
as the substrate were measured spectrophotometrically with the following modifications.
Pro- and Antitumorigenic Activity of Xanthine
oxidase, allopurinol, xanthine
, hydroxylamine, N-(1-naphthyl)-ethylenediamine dihydrochloride, sulfanilic acid, ethylenediamine tetra acetate (EDTA), butylated hydroxytoluene (BHT), gallic acid, 2, 4, 6-tripyridyl-s-triazine (TPTZ), 1,1-diphenyl-2- picrylhydrazyl (DPPH), acetylthiocholine iodide, 5,5- dithiobis [2-nitro benzoic acid (DTNB) were purchased from Merck (Germany) and sigma aldrich.
The XOR can specifically bind to endothelial cells and cell-bound XOR has been reported to produce radicals, which are inaccessible to CuZn-superoxide dismutase thus, during ischemia, ATP is degenerated to xanthine
and hypoxanthine, thereby increasing XOR substrate levels, which leads to increased superoxide production.
Therapeutic effects of xanthine
oxidase inhibitors: renaissance half a century after the discovery of allopurinol.
Our results revealed that an extract prepared from the leaves of Peumus boldus exhibited moderate inhibitory activities against pancreatic lipase (PL) and xanthine
oxidase (XO) but pronounced inhibitory activities on [alpha]-glucosidase.
In the literature, it has been reported that the presence of higher XO activity in ischemic tissue is due to the conversion of the xanthine
dehydrogenase enzyme into XO by a calcium-mediated protease catalyst in the ischemia mediator (GRACE, 1994).
Key words: Urolithiasis; xanthinuria, xanthine
XO Determination: Xanthine
oxidase enzyme activity was measured by spectrophotometric determination of absorbance level of uric acid formation from xanthine
at a wave length of 293 nm and the results were expressed in terms of mIU/mg .
The uricosuric agent probenecid was recognized as an alternative first-line agent for urate lowering in patients who could not tolerate or had a contraindication to at least one xanthine