Rat liver xanthine oxidoreductase: Effect of adenine on the oxidase and dehydrogenase activities

Research output: Contribution to journalArticle


Xanthine oxidase (XO) and total oxidase plus dehydrogenase (XO+XDH) activities from rat liver were measured in the presence or absence of adenine in extracts prepared with or without DTT/PMSF in homogenization buffer. Presence of adenine in extracts, prepared with or without DTT/PMSF, caused a 4560% decrease in XO and XO+XDH activities. Removal of adenine by dialysis from extracts prepared with or without DTT/PMSF resulted in the recovery of XO and XO+XDH activities to almost their pre-dialysis control levels. Enzyme activity after 24hr storage at -20°C depended on the presence or absence of DTT/PMSF and adenine, with both XO and XO+XDH activities being lower in extracts with the combined presence of DTT/PMSF and adenine. Incubation of extracts at 37°C for 30 minutes resulted in increased XO and XO+XDH activities, however, adenine-treated samples did not differ from their pre-incubation activities. The molecular mass of the enzyme from control and adenine-treated extracts was unchanged (300 kDa). Adenine-treated extracts prepared with or without DTT/PMSF showed higher D/O ratios in all post-dialysis samples when compared with their pre-dialysis ratios. The results suggest that adenine may play a role in preventing the dehydrogenase to oxidase conversion during extract preparation, storage, overnight dialysis and heat treatment.

Original languageEnglish (US)
Pages (from-to)6-17
Number of pages12
JournalItalian Journal of Biochemistry
Issue number1
StatePublished - Mar 1 2007



  • Adenine
  • Dialysis
  • Rat liver
  • Xanthine dehydrogenase
  • Xanthine oxidase

ASJC Scopus subject areas

  • Biochemistry

Cite this