钠/葡萄糖共转运体基因家族成员slc5a8对b -复合物维生素烟酸钠偶联和电致转运的研究

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郭波，费玉杰，宫内森，庄林，普拉萨德，甘纳帕提

钠/葡萄糖共转运体基因家族成员slc5a8对b -复合物维生素烟酸钠偶联和电致转运的研究

生物化学学报，2005年5月15日;388(Pt 1):309-16。

PubMed ID

15651982 (PubMed视图

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摘要

钠偶联单羧酸盐转运蛋白;slc5a8)是乳酸、丙酮酸和短链脂肪酸的Na+偶联转运体。与这些已知的SMCT底物类似，水溶性复合b族维生素烟酸在生理条件下也以单羧酸阴离子(烟酸)的形式存在。因此，我们评估了SMCT介导烟酸摄取的能力。在哺乳动物细胞中，克隆小鼠SMCT (slc5a8)诱导尼古丁摄取。smct诱导的摄取是Na+依赖性的。摄取过程的米凯利常数为296+/-88微米。Na+活化动力学表明，至少有2个Na+离子参与了该过程。在测试的各种结构类似物中，烟酸盐是最有效的底物。烟酰胺和甲基烟酸不能被转运体识别。 2-pyrazine carboxylate and isonicotinate interacted with the transporter to a moderate extent. SMCT-mediated uptake of nicotinate was inhibited by lactate and pyruvate. In the Xenopus laevis oocyte expression system, SMCT-mediated nicotinate transport was electrogenic, as evident from the nicotinate-induced inward currents under voltage-clamp conditions. Substrate-induced currents in this expression system corroborated the substrate specificity determined in the mammalian cell expression system. The kinetic parameters with regard to the affinity of the transporter for nicotinate and the Hill coefficient for Na+ activation, determined by using the oocyte expression system, were also similar to those obtained from the mammalian cell expression system. We conclude that SMCT functions not only as a Na+-coupled transporter for short-chain fatty acids and lactate but also as a Na+-coupled transporter for the water-soluble vitamin nicotinic acid.

引用本文的药物库数据

药物转运蛋白

药物	转运体	种类	生物	药理作用	行动
肌醇烟酸酯	钠偶联单羧酸转运蛋白1	蛋白质	人类	未知的	底物	细节
烟酸	钠偶联单羧酸转运蛋白1	蛋白质	人类	未知的	不可用	细节