. "Catalysis of the transfer of a nucleoside, a nucleobase linked to either beta-D-ribofuranose (ribonucleoside) or 2-deoxy-beta-D-ribofuranose, (a deoxyribonucleotide) from one side of a membrane to the other." . . "intracellular nucleoside transmembrane transporter activity" . "nucleoside transmembrane transporter activity" . . . . . . . . . . . .