Inhibition of Partially Purified Xanthine Oxidase Activity from Sera of Patients with Gout

Abstract

In this research, xanthine oxidase (XO) was partially purified from sera of patients with gout, by dialysis and anion exchange chromatography techniques. One protein peak of XO activity was obtained with specific activity (0.149) unit/mg protein and with purification fold of (496.66) compared to crude enzyme.Inhibition of partially purified XO was studied by allopurinol, caffeine and allopurinol with caffeine as a prodrug. The lower concentration of each inhibitor which exhibited maximal inhibitory effect was (10-7) mM. The inhibition type of XO by using these inhibitors at these concentrations competitive inhibition.The results show that Km value without inhibitors was (40) mM. However, was Km values were (58.8), (100), and (125) mM with inhibitors respectively, and Vmax value remained stable (0.135) unit/ml. The inhibition constant Ki values were (0.68), (0.4) and (0.32) mM, respectively.Accordingly, these results indicate that inhibitory effect of allopurinol with caffeine was better than caffeine, and caffeine was better than allopurinol. We suggest the intake of herbs and plants containing caffeine alone and/or with allopurinol drug to prevent or treat gout.