Effects of purine analogs on P1-mediated (A) and P2-mediated (B) transport of 0.04 μM [3H]adenosine and H2-mediated transport of 0.05 μM [3H]hypoxanthine (C) by wild-type Trypanosoma brucei brucei bloodstream forms. (A and B) ▪, 2′-deoxyadenosine; □, NA42; •, NA114. (C) ▪, NA134; ○, adenine. Inhibition is expressed as a percentage of radiolabel transport in the absence of inhibitor. P1-mediated transport was assessed in the presence of 100 μM adenine and P2-mediated transport was assessed in the presence of 1 mM inosine, as described previously (11). The data points are the averages of triplicate determinations, and error bars are standard errors.