Inhibition of xanthine oxidase by synthetic cytokinin analogues

Shiow Yunn Sheu, Yu Chan Lin, Hsüch Ching Chiang

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11 Citations (Scopus)


Thirteen synthetic cytokinin analogues were tested for their inhibitory effects on xanthine oxidase. The enzyme, xanthine oxidase catalyses the oxidation of hypoxanthine to xanthine and of xanthine to uric acid, which has a λmax of 295 nm, forming the basis for a spectrophotometric assay of the activity of xanthine oxidase. The results showed that 8-azaadenine(1), 4-amino-6-hydroxypyrazolo [3,4-d] pyrimidine(4), 4-amino-6-mercaptopyrazolo [3,4-d] pyrimidine(5) and 4-aminopyrazolo [3,4-d] pyrimidine(6) display inhibitory effects on xanthine oxidase with an order of activity of IC50 = 0.54, 5.91, 8.17 and 25.46 μM, respectively. Their apparent inhibition constants (Ki) were 0.66, 1.54, 6.61 and 26.79 μM, and induced mixed(competitive-non-competitive), competitive, mixed (competitive-non-competitive), and competitive types of inhibition respectively, with respect to the substrate xanthine.

Original languageEnglish
Pages (from-to)1043-1049
Number of pages7
JournalAnticancer Research
Issue number2 A
Publication statusPublished - 1997


  • 4-amino-6-mercaptopyrazolo [3,4-d] pyrimidine
  • 8-azaadenine,4-amino-6-hydroxypyrazolo[3,4-d]pyrimidine
  • Anti-tumor
  • Antibacterial
  • Synthetic cytokinin analogues
  • Xanthine oxidase inhibitors

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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