Proton-coupled transporter that transports a wide spectrum of oxo derivatives of heterocyclic nitrogen compounds, including allantoin, uric acid and xanthine, but not adenine. Mediates high affinity transport of uracil and 5-fluorouracil (a toxic uracil analog). Mediates transport of free pyrimidines and may function during early seedling development in salvage pathways, by the utilization of pyrimidines from seed storage tissue. Expressed in root xylem, cotyledons and leaves (PubMed:15308648). Expressed in leaf blades, petioles, trichomes, stems, flower stigma, the upper part of pedicels, sepals, and the top and bottom parts of carpels in siliques (PubMed:16738859). During seedling development, expression is hardly detected during the first 2 days after imbibition, and then increases to reach a peak after 9 days. Belongs to the plant ureide permease (TC 2.A.7.19) family. Truncated N-terminus.