有机阴离子多肽介导运输有机阴离子/ HCO3 -交换。

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Satlin LM,阿明V, Wolkoff哦

有机阴离子多肽介导运输有机阴离子/ HCO3 -交换。

生物化学杂志。1997年10月17日;272 (42):26340 - 5。

PubMed ID

9334206 (在PubMed

]

文摘

有机阴离子运输多肽(oatp)是一个完整的膜蛋白的克隆鼠肝脏调节Na +独立运输有机阴离子sulfobromophthalein和牛磺胆酸等。先前的研究在大鼠肝细胞表明有机阴离子吸收与基地有关交换。为了更好地描述oatp-mediated有机离子吸收的机理,我们对运输的牛磺胆酸盐海拉细胞线稳定转染与oatp的监管下zinc-inducible启动子(Shi, X。巴姨,S。、福特、a . C。伯克,r D。Jacquemin E。,Hagenbuch B。,迈耶,p . J。Wolkoff, a . w .(1995)生物。270年化学,25591 - 25595)。而noninduced转染细胞显示几乎没有[3 h]牛磺胆酸盐的摄取,牛磺胆酸盐吸收通过诱导细胞Na +独立和饱和(公里= 19.4 + / - 3.3 microM;Vmax = 62.2 + / - 1.4 pmol /分钟/毫克蛋白;n = 3)。测试是否有机阴离子运输耦合HCO3 -挤压,我们比较的taurocholate-dependent HCO3 -射流从alkali-loaded noninduced和诱导细胞。 Monolayers grown on glass coverslips were loaded with the pH-sensitive dye 2', 7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; intracellular pH (pHi) was measured by excitation ratio fluorometry. Noninduced and induced cells were alkalinized to an equivalent pHi ( approximately 7.7) by transient exposure to a 50 mM HCO3-, Cl--free solution. In the absence of extracellular Cl- and taurocholate, isohydric reduction of superfusate HCO3- concentration from 50 to 25 mM resulted in an insignificant change in pHi over time (dpHi/dt) in both groups. Addition of 25 microM taurocholate to the superfusate led to a rapid fall in pHi in induced (-0.037 +/- 0.011 pH units/min to pHi of 7.41 +/- 0.14) but not in noninduced (0.003 +/- 0.006 pH units/min to pHi of 7.61 +/- 0.08) cells (p < 0.03). These data indicate that oatp-mediated taurocholate transport is Na+-independent, saturable, and accompanied by HCO3- exchange. We conclude that organic anion/base exchange is an important, potentially regulatable component of oatp function.

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药物转运蛋白

药物	转运体	类	生物	药理作用	行动
牛磺胆酸	溶质载体有机阴离子转运蛋白家族成员1 a2	蛋白质	人类	未知的	底物 抑制剂 诱导物	细节