TABLE 6

Lack of effects of 8-aminohypoxanthine (8-AminoHX) on xanthine oxidase

Increasing amounts of xanthine oxidase were incubated for 15 minutes at 30°C in 50 mmol/L of KH2PO4 with substrate (hypoxanthine) and the potential inhibitor (8-aminohypoxanthine). The remaining hypoxanthine and 8-aminohypoxanthine (8-aminoHX) and generated products (xanthine, uric acid, and 8-aminoxanthine) were measured by HPLC and quantified as area under the chromatographic peak following equal volume injections (4 µl) of the reaction mixture.

Reaction ComponentsHPLC Results
Xanthine Oxidase
(µg)
[Hypoxanthine]
(µmol/L)
[8-AminoHX]
(µmol/L)
Hypoxanthine
(Peak Area)
Xanthine
(Peak Area)
Uric Acid
(Peak Area)
8-AminoHX
(Peak Area)
8-Aminoxanthine
(Peak Area)
02000277NDNDNDND
0.2200018448153NDND
0.2200200178491541979ND
0.420009224271NDND
0.42002006419297105120
12000NDND406NDND
1200200NDND39979668
22000NDND437NDND
2200200NDND404586108
  • ND, not detected.