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

High performance liquid chromatography with TSK 5000 PW or TSK 6000 PW size exclusion columns combined with a 125I labelled hyaluronic acid binding protein assay was used to study the effects of oxygen derived free radicals on synovial fluid hyaluronate. A continuous flux of free radicals was generated by the xanthine oxidase/hypoxanthine system. When the free radical flux was generated with xanthine oxidase/hypoxanthine in the presence of the iron chelator desferrioxamine and the hydroxyl radical scavenger mannitol a 30-50% decrease in hyaluronate peak was detected, but the molecular weight of synovial fluid hyaluronate remained almost unchanged as a result of reaction with superoxide radicals and hydrogen peroxide. When trace amounts of iron and EDTA were present in the reaction mixture depolymerisation of synovial fluid hyaluronate occurred, and it reached a final molecular weight of about 13,500 daltons. These results suggest that superoxide and hydroxyl radicals may have a different mode of action on synovial fluid hyaluronate. Superoxide radicals and hydrogen peroxide do not induce depolymerisation but, rather, change the molecular configuration of synovial fluid hyaluronate.
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PMID:Oxygen derived free radicals and synovial fluid hyaluronate. 171 35

Oxygen-derived free radicals (ODFR) depolymerized synovial-fluid (SF) hyaluronic acid (HA) when hypoxanthine/xanthine oxidase (HX/XAO) was used as the radical generator. The molecular-weight distribution of ODFR-induced SF HA degradation products was determined using high performance liquid chromatography (HPLC) with TSK 5000 PW or TSK 6000 PW size-exclusion columns and simultaneously using 125I-labelled hyaluronate-binding protein (125I-HABP) assay. The exposure of SF HA to hydroxyl-radical flux resulted in the formation of a degradation product having a molecular weight of 13.5 X 10(3) daltons, from which no further degradation was achieved. If the iron chelator desferrioxamine and hydroxyl-radical scavenger mannitol were present in the reaction mixture, the HA peak decreased by 30-50%, as a result of reaction with superoxide radical and hydrogen peroxide. These results show that superoxide radical and hydroxyl radical may have different modes of action on SF HA. The molecular-weight distribution of serum HA from patients with rheumatoid arthritis varied in different individuals and ranged between 275 X 10(3) and 650 X 10(3).
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PMID:Reactive oxygen species and hyaluronate in serum and synovial fluid in arthritis. 221 Sep 71