Copper transport and kinetics in cultured C6 rat glioma cells.
Copper transport and kinetics in cultured C6 rat glioma cells.
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DOI：
10.1152/ajpcell.1995.269.4.c892
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发表时间：
1995-10
期刊：
影响因子：
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通讯作者：
Y. Qian;E. Tiffany‐Castiglioni;Edward D. Harris
中科院分区：
文献类型：
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作者：
Y. Qian;E. Tiffany‐Castiglioni;Edward D. Harris
C6大鼠胶质瘤细胞积聚和外排67Cu。随着67Cu浓度的增加，两个过程均表现出饱和动力学。Michaelis常数（Km）为0.63 +/- 0.14 μ m；最大流速（Vmax）为3.29±0.57 pmol Cu。毫克蛋白- 1. - min - 1。射流Km为0.15 +/- 0.06微米；Vmax为1.08±0.71 pmol Cu。毫克蛋白- 1. - min - 1。对氯甲苯甲酸盐（p-CMB）完全阻断67Cu的外排，但对摄取Km和Vmax没有影响。50 min后，细胞内67Cu的颗粒和可溶组分平均分配。p- cmb处理的细胞积累了更多的67Cu，但与颗粒（膜）部分结合的< 10%。铅在不影响67Cu吸收Km和Vmax的情况下增加了67Cu的积累。这些数据表明，C6细胞中输入和输出Cu的载体是不同的或在两种不同的细胞环境中工作。外排是一个巯基依赖的过程，受铅的抑制。这些数据与p型atp酶参与细胞内铜的外排以及Pb抑制外排机制的可能性一致。
C6 rat glioma cells accumulate and efflux 67Cu. Both processes showed saturation kinetics with increasing 67Cu concentration. The Michaelis constant (Km) for uptake was 0.63 +/- 0.14 microM; maximum velocity (Vmax) was 3.29 +/- 0.57 pmol Cu.mg protein-1.min-1. The Km for efflux was 0.15 +/- 0.06 microM; Vmax was 1.08 +/- 0.71 pmol Cu.mg protein-1.min-1. p-Chloromercuribenzoate (p-CMB) totally blocked 67Cu efflux but had no effect on Km or Vmax of uptake. Total 67Cu in the cell after 50 min was partitioned equally between particulate and soluble fractions. p-CMB-treated cells accumulated more 67Cu, but < 10% was bound to the particulate (membrane) fraction. Pb also increased 67Cu accumulation without affecting Km and Vmax of 67Cu uptake. These data suggest that carriers for import and export of Cu in C6 cells are distinct or operate in two different cellular environments. Efflux is a sulfhydryl-dependent process subject to inhibition by Pb. The data are consistent with a P-type ATPase in the efflux of Cu from cells and the potential for Pb to inhibit the efflux mechanism.