FIGURE 10.
AAH stability and kinetics. A, purified recombinant L. donovani AAH was incubated with 1 unit of xanthine oxidase and varying concentrations of adenine over a 90-s time course, and the absorbance was monitored at 292 nm. Kinetic constants were computed using Michaelis-Menten and Hanes-Woolf (inset) algorithms from GraphPad Prism. B, inhibition of AAH activity by dCF was followed over a 90-s time course, with the formation of adenine (Ade) monitored as detailed previously above at 0 (■), 10 (▴), 20 (▾), or 30 (♦) μm dCF. Kinetic constants were computed via the Michaelis-Menten algorithm within GraphPad Prism. C, apparent Km values calculated in B were replotted as a function of dCF concentration, and the Ki value for dCF was determined from the negative value of the x-intercept.