Enzymes
| UniProtKB help_outline | 7 proteins |
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- Name help_outline L-ascorbate Identifier CHEBI:38290 (Beilstein: 3549814; CAS: 299-36-5) help_outline Charge -1 Formula C6H7O6 InChIKeyhelp_outline CIWBSHSKHKDKBQ-JLAZNSOCSA-M SMILEShelp_outline [H][C@@]1(OC(=O)C(O)=C1[O-])[C@@H](O)CO 2D coordinates Mol file for the small molecule Search links Involved in 34 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline Na+ Identifier CHEBI:29101 (CAS: 17341-25-2) help_outline Charge 1 Formula Na InChIKeyhelp_outline FKNQFGJONOIPTF-UHFFFAOYSA-N SMILEShelp_outline [Na+] 2D coordinates Mol file for the small molecule Search links Involved in 254 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:69883 | RHEA:69884 | RHEA:69885 | RHEA:69886 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Human Na(+)-dependent vitamin C transporter 1 (hSVCT1): primary structure, functional characteristics and evidence for a non-functional splice variant.
Wang H., Dutta B., Huang W., Devoe L.D., Leibach F.H., Ganapathy V., Prasad P.D.
We report here on the cloning and functional characterization of human Na(+)-dependent vitamin C transporter 1 (SVCT1). The human SVCT1 cDNA, obtained from a Caco2 cell cDNA library, encodes a protein of 598 amino acids with 12 putative transmembrane domains. The SVCT1-specific transcript, 2.4 kb ... >> More
We report here on the cloning and functional characterization of human Na(+)-dependent vitamin C transporter 1 (SVCT1). The human SVCT1 cDNA, obtained from a Caco2 cell cDNA library, encodes a protein of 598 amino acids with 12 putative transmembrane domains. The SVCT1-specific transcript, 2.4 kb in size, is expressed in kidney, liver, small intestine, thymus and prostate. When expressed heterologously in HRPE cells, SVCT1 mediates the transport of ascorbate, the reduced form of vitamin C, in a Na(+)-dependent manner. The transporter is specific for ascorbate with a K(t) of approximately 75 microM. The relationship between the cDNA-specific uptake rate of ascorbate and Na(+) concentration is sigmoidal with a Na(+):ascorbate stoichiometry of 2:1, indicating that the transport process is electrogenic. In Caco2 cells and in normal human intestine, SVCT1 also exists as a non-functional splice variant with a four amino acid sequence inserted between E-155 and V-156. The splice variant results from the use of a donor site 12 bp downstream of the normal donor site. << Less
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Cloning and functional characterization of the human sodium-dependent vitamin C transporters hSVCT1 and hSVCT2.
Daruwala R.C., Song J., Koh W.S., Rumsey S.C., Levine M.
Two sodium-dependent vitamin C transporters, hSVCT1 and hSVCT2, were cloned from a human kidney cDNA library. hSVCT1 had a 1797 bp open reading frame encoding a 598 amino acid polypeptide. The 1953 bp open reading frame of hSVCT2 encoded a 650 amino acid polypeptide. Using a Xenopus laevis oocyte ... >> More
Two sodium-dependent vitamin C transporters, hSVCT1 and hSVCT2, were cloned from a human kidney cDNA library. hSVCT1 had a 1797 bp open reading frame encoding a 598 amino acid polypeptide. The 1953 bp open reading frame of hSVCT2 encoded a 650 amino acid polypeptide. Using a Xenopus laevis oocyte expression system, both transporters were functionally expressed. By Eadie-Hofstee transformation the apparent K(m) of hSVCT1 for ascorbate was 252.0 microM and of hSVCT2 for ascorbate was 21.3 microM. Both transporters were sodium-dependent and did not transport dehydroascorbic acid. Incubation of oocytes expressing either transporter with phorbol 12-myristate 13-acetate (PMA) inhibited ascorbate transport activity. Availability of the human transporter clones may facilitate new strategies for determining vitamin C intake. << Less
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Human placental sodium-dependent vitamin C transporter (SVCT2): molecular cloning and transport function.
Rajan D.P., Huang W., Dutta B., Devoe L.D., Leibach F.H., Ganapathy V., Prasad P.D.
We report here on the cloning and functional characterization of human SVCT2, a sodium-dependent vitamin C (ascorbate) transporter. The hSVCT2 cDNA obtained from a human placental choriocarcinoma cell cDNA library, codes for a protein of 650 amino acids with a predicted molecular mass of 70 kDa. A ... >> More
We report here on the cloning and functional characterization of human SVCT2, a sodium-dependent vitamin C (ascorbate) transporter. The hSVCT2 cDNA obtained from a human placental choriocarcinoma cell cDNA library, codes for a protein of 650 amino acids with a predicted molecular mass of 70 kDa. At the level of amino acid sequence, the human SVCT2 exhibits 95% identity to its rat homolog. When functionally expressed in mammalian cells, hSVCT2 induces the transport of ascorbic acid. The transport process induced by hSVCT2 is Na(+)-dependent and is specific for ascorbate. The Michaelis-Menton constant (K(t)) for the transport of ascorbate in cDNA-transfected cells is 69 +/-5 microM. The relationship between the cDNA-specific uptake rate of ascorbate and Na(+) concentration is sigmoidal with a Na(+):ascorbate stoichiometry of 2:1. Northern blot analysis shows that SVCT2-specific transcripts are present in heart, brain, placenta, and liver and is absent in lung and skeletal muscle. The size of the principal transcript is approximately 7.5 kb. << Less
Biochem. Biophys. Res. Commun. 262:762-768(1999) [PubMed] [EuropePMC]