Thiamine transporter 1 (SLC19A2), Thiamine transporter 2 (SLC19A3) (SLC19A2, SLC19A3)

The main pyridoxine transporters in humans are Thiamine transporter 1 (SLC19A2) and Thiamine transporter 2 (SLC19A3), members of the solute carrier (SLC) family responsible for the high-affinity uptake of both thiamine (vitamin B1) and pyridoxine (vitamin B6)[2][3][4]. These transporters are expressed in the intestinal epithelium and other tissues, enabling absorption of non-phosphorylated B6 vitamers under physiologically acidic conditions typical of the intestinal microenvironment[3]. Their substrate specificity is determined by a unique set of amino acid residues in the transmembrane domains, with human SLC19A3 distinct in transporting pyridoxine compared to rodent orthologs[4]. They are implicated in competitive drug-nutrient interactions and are potential biomarkers or therapeutic targets, especially where transporter function is genetically impaired[2][3]. The designation "Pyridoxine transporter" is functionally descriptive but not a canonical protein name; for structured data, SLC19A2 and SLC19A3 should be used[2][3][4].

Other names

Thiamine transporter 1Thiamine transporter 2Solute carrier family 19 member 2Solute carrier family 19 member 3THTR-1THTR-2Vitamin B1 transporter

Competitive substrate inhibition (thiamine and pyridoxine compete for transport); Drug interaction via transporter occupancy or competition