Figure 2
Difference of inhibitory effects of febuxostat on bovine and Rhodobacter capsulatus XORs.
(a)–(c): Structures of (a) allopurinol, (b) oxipurinol and (c) febuxostat. (d) Activity in the presence of various concentrations of febuxostat as a percentage of that in the absence of inhibitor. 
, bXOR; 
, RcXOR; 
, RcXOR H198N mutant. (e) Kinetics of xanthine-NAD+ inhibition. Lineweaver-Burk plots of xanthine-NAD+ activity of RcXOR in the presence of febuxostat. Final concentration of XOR (AFR = 401) was 2.4 nM. Final concentrations of febuxotat: ×, no inhibitor; 
, 5 µM; 
, 10 µM; 
, 15 µM; 
, 20 µM. (inset) Secondary plots. The Ki value was obtained from secondary plots of slope of the Lineweaver-Burk plot versus inhibitor concentration.
