TY - JOUR
T1 - Human placental sodium-dependent vitamin C transporter (SVCT2)
T2 - Molecular cloning and transport function
AU - Rajan, D. Prasanna
AU - Huang, Wei
AU - Dutta, Binita
AU - Devoe, Lawrence D
AU - Leibach, Frederich H.
AU - Ganapathy, Vadivel
AU - Prasad, Puttur D
N1 - Funding Information:
This work was supported by the National Institutes of Health Grant HD33347 to V. Ganapathy.
PY - 1999/9/7
Y1 - 1999/9/7
N2 - 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 μM. 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 ~ 7.5 kb.
AB - 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 μM. 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 ~ 7.5 kb.
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U2 - 10.1006/bbrc.1999.1272
DO - 10.1006/bbrc.1999.1272
M3 - Article
C2 - 10471399
AN - SCOPUS:0033533578
SN - 0006-291X
VL - 262
SP - 762
EP - 768
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 3
ER -