Uptake of taurocholic acid into isolated rat-liver cells.
Uptake of taurocholic acid into isolated rat-liver cells.
复制标题
牛磺胆酸被分离的大鼠肝细胞吸收。
DOI：
10.1111/j.1432-1033.1975.tb02199.x
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
H. Greim
中科院分区：
文献类型：
--
作者：
L. Schwarz;R. Burr;M. Schwenk;E. Pfaff;H. Greim
研究了离体大鼠肝细胞摄取牛磺胆酸的结合和转运特征。1.牛磺胆酸盐在细胞表面的吸附在小于15秒内终止。确定了0.55mM的Ks和3.8nmol/mg细胞蛋白的总结合能力。2.牛磺胆酸盐的摄取速率遵循Michaelis-Menten动力学，Km = 19 μ M，V = 1.7 nmol/mg蛋白质min。在pH 6.5 - 8.0之间有一个较宽的吸收最佳pH值。4.活化能为29 kcal/mol。在高牛磺胆酸盐浓度下，在Arrhenius图中观察到不寻常的向上弯曲。5.牛磺胆酸盐摄取被牛磺鹅脱氧胆酸盐竞争性抑制（Ki = 9 μ M）。它是非竞争性抑制溴磺酞（Ki = 3 μ M）。6.在生理牛磺胆酸盐浓度下，观察到牛磺胆酸盐的200倍细胞内积累。7.抗霉素A、羰基氰间氯苯腙、哇巴因均可抑制摄取约75%。8.用K+或蔗糖替代细胞外Na+导致摄取减少75%。9.它的结论是，牛磺胆酸钠的摄取是一个载体介导的过程，并建议，细胞内积累的能量是由Na+的共转运。
Binding and transport characteristics for uptake of taurocholic acid by isolated rat liver cells were studied. 1. An adsorption of taurocholate to the cell surface is terminated in less than 15 s. A Ks of 0.55 mM and a total binding capacity of 3.8 nmol/mg cell protein is determined. 2. The rate of uptake of taurocholate follows Michaelis-Menten kinetics with Km = 19 muM and V = 1.7 nmol/mg protein min. 3. There is a broad pH optimum for uptake between pH 6.5 -- 8.0. 4. The activation energy amounts to 29 kcal/mol. At high taurocholate concentration an unusual upward bend is observed in the Arrhenius plot. 5. Taurocholate uptake is competitively inhibited by taurochenodeoxycholate (Ki = 9 muM). It is noncompetitively inhibited by bromosulfophthalein (Ki = 3 muM). 6. At physiological taurocholate concentrations a 200-fold intracellular accumulation of taurocholate is observed. 7. Uptake is inhibited by about 75% by either antimycin A, carbonylcyanide m-chlorophenyl-hydrazone, ouabain. 8. Replacement of extracellular Na+ by either K+ or sucrose results in a 75% decrease of uptake. 9. It is concluded that taurocholate uptake is a carrier-mediated process, and suggested that the energy for intracellular accumulation is made available by cotransport of Na+.