Human vitamin C (L-ascorbic acid) transporter SVCT1.

摘要: Abstract In human, vitamin C ( l -ascorbic acid) is an essential micronutrient required for array of biological functions including enzymatic reactions and antioxidation. We describe here the molecular cloning a novel human cDNA encoding transporter SVCT1. SVCT1 largely confined to bulk-transporting epithelia (e.g., kidney small intestine) with putative alternative-splice product present in thymus. Applying radiotracer voltage-clamp approaches cRNA-injected Xenopus oocytes, we found that mediates saturable, concentrative, high-affinity acid transport K 0.5 = 50–100 μM) electrogenic can be inhibited by phloretin. displays exquisite substrate selectivity, greatly favoring over its isomers d -isoascorbic dehydroascorbic 2- or 6-substituted analogues, whereas glucose nucleobases are excluded. have mapped SLC23A2 gene (coding SVCT1) chromosome 5 band 5q31.2-31.3, within region commonly deleted malignant myeloid (leukemia) diseases. addition, demonstrated SLC23A1 related (SVCT2) widely distributed brain, retina, host endocrine neuroendocrine tissues. The identification transporters now provides tools which investigate their roles metabolism health disease.