FIGURE 5.

Uptake of 5-[¹⁴C]methyltetrahydrofolate in Xenopus-expressing PfFT2. Oocytes injected with PfFT2 accumulated 5-[¹⁴C]MTHF at values significantly above the water-control. hRFC1 is known to have high affinity for reduced folates (K_m 2–4 μm), and used as positive control here it validates the expression system for uptake of this reduced folate. Data are the mean and S.D. of groups with 24–36 oocytes. PBN used at 200 μm significantly reduced 5-[¹⁴C]MTHF uptake in both groups. Significance values between groups of injected oocytes was calculated with non-parametric Mann-Whitney U test using data for at least three different experiments (n = 3).