Human placental sodium-dependent vitamin C transporter (SVCT2): Molecular cloning and transport function
Human placental sodium-dependent vitamin C transporter (SVCT2): Molecular cloning and transport function
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DOI：
10.1006/bbrc.1999.1272
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发表时间：
1999-09-07
影响因子：
3.1
通讯作者：
Prasad, PD
中科院分区：
文献类型：
--
作者：
Rajan, DP;Huang, W;Prasad, PD
我们在这里报告的克隆和功能特性的人SVCT 2，钠依赖性维生素C（抗坏血酸）转运。从人胎盘绒毛膜癌细胞cDNA文库获得的hSVCT 2 cDNA编码650个氨基酸的蛋白质，预测分子量为70 kDa。在氨基酸序列水平上，人SVCT 2与其大鼠同源物具有95%的同一性。当在哺乳动物细胞中功能性表达时，hSVCT 2诱导抗坏血酸的转运。由hSVCT 2诱导的转运过程是Na+依赖性的，并且对抗坏血酸具有特异性。在cDNA转染的细胞中转运抗坏血酸的Michaelis-Menton常数（K-t）为69 +/- 5 μ M。抗坏血酸的cDNA特异性摄取速率与Na+浓度之间的关系是S形的，Na+：抗坏血酸的化学计量为2：1。北方印迹分析显示SVCT 2特异性转录物存在于心脏、脑、胎盘和肝脏中，而在肺和骨骼肌中不存在。主转录本的大小类似于7.5kb。(C)北京：科学出版社.
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 mu M. 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 similar to 7.5 kb. (C) 1999 Academic Press.