TABLE 1

Initial rates of uptake of BR and TR in S. cerevisiae producing human recombinant nucleoside transporters Time courses of uptake of 1 μ M ³H-labeled uridine, TR, or BR by hENT1-, hENT2-, hCNT1-, or hCNT3-producing yeast were measured in the presence or absence of excess uridine as described under Materials and Methods. Initial rates (in picomoles per milligram of protein per minute) ± S.E. of uptake were calculated from the slopes of the linear regression lines using GraphPad Prism software version 3.02; rates in the presence of 10 mM nonradioactive uridine were subtracted from rates in its absence to give rates of mediated uptake (i.e., transport).