The Folate-Biopterin Transporter (FBT) Family (TC 2.A.71)The only functionally characterized members of the family are from protozoa and include FT1, the major folate transporter in Leishmania, and BT1, the Leishmania biopterin/folate transporter. A related protein in Trypanosoma brucei, ESAGIO, shows weak folate/biopterin transport activity. [Cell envelope, Other]