RGD Reference Report - A family of mammalian Na+-dependent L-ascorbic acid transporters. - Rat Genome Database

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A family of mammalian Na+-dependent L-ascorbic acid transporters.

Authors: Tsukaguchi, H  Tokui, T  Mackenzie, B  Berger, UV  Chen, XZ  Wang, Y  Brubaker, RF  Hediger, MA 
Citation: Tsukaguchi H, etal., Nature 1999 May 6;399(6731):70-5.
RGD ID: 634186
Pubmed: (View Article at PubMed) PMID:10331392
DOI: Full-text: DOI:10.1038/19986

Vitamin C (L-ascorbic acid) is essential for many enzymatic reactions, in which it serves to maintain prosthetic metal ions in their reduced forms (for example, Fe2+, Cu+), and for scavenging free radicals in order to protect tissues from oxidative damage. The facilitative sugar transporters of the GLUT type can transport the oxidized form of the vitamin, dehydroascorbic acid, but these transporters are unlikely to allow significant physiological amounts of vitamin C to be taken up in the presence of normal glucose concentrations, because the vitamin is present in plasma essentially only in its reduced form. Here we describe the isolation of two L-ascorbic acid transporters, SVCT1 and SVCT2, from rat complementary DNA libraries, as the first step in investigating the importance of L-ascorbic acid transport in regulating the supply and metabolism of vitamin C. We find that SVCT1 and SVCT2 each mediate concentrative, high-affinity L-ascorbic acid transport that is stereospecific and is driven by the Na+ electrochemical gradient. Despite their close sequence homology and similar functions, the two isoforms of the transporter are discretely distributed: SVCT1 is mainly confined to epithelial systems (intestine, kidney, liver), whereas SVCT2 serves a host of metabolically active cells and specialized tissues in the brain, eye and other organs.

Annotation

Gene Ontology Annotations    

Biological Process

Cellular Component

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Slc23a1  (solute carrier family 23 member 1)
Slc23a2  (solute carrier family 23 member 2)

Objects referenced in this article
Gene SLC23A1 solute carrier family 23 member 1 Homo sapiens
Gene SLC23A2 solute carrier family 23 member 2 Homo sapiens

Additional Information