ASCORBIC-ACID TRANSPORT AND DISTRIBUTION IN HUMAN B-LYMPHOCYTES
ASCORBIC-ACID TRANSPORT AND DISTRIBUTION IN HUMAN B-LYMPHOCYTES
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DOI：
10.1006/abbi.1995.1155
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发表时间：
1995-02-20
影响因子：
3.9
通讯作者：
LEVINE, M
中科院分区：
文献类型：
--
作者：
BERGSTEN, P;YU, R;LEVINE, M
用人B淋巴细胞研究抗坏血酸（维生素C）的转运。维生素由两种成分运输。第一个是高亲和活性，表观Km为7-10 μ M，V-max为0.14 mM/h（3.11 × 10（-4）μ mol × h（-1）× mg蛋白质（-1））。活性是浓度和温度依赖性的，饱和，并抑制羰基氰-p-三氟甲氧基苯腙和哇巴因，并产生抗坏血酸积累对浓度梯度。第二种成分的动力学是不确定的，因为抗坏血酸不积累对浓度梯度。亚细胞分级分离显示，人B淋巴细胞中的细胞内抗坏血酸>90%定位于胞质溶胶，而不是蛋白质结合。高亲和力的抗坏血酸运输的动力学参数可以有效地与血浆浓度通常在人类中发现。(C)出版社：Academic Press
Ascorbic acid (vitamin C) transport was investigated inhuman B lymphocytes. The vitamin was transported by two components. The first was a high-affinity activity with an apparent K-m of 7-10 mu M and V-max of 0.14 mM/h (3.11 X 10(-4) mu mol X h(-1) X mg protein(-1)). The activity was concentration and temperature dependent, saturable, and inhibited by carbonylcyanide-p-trifluoromethoxyphenylhydrazone and ouabain and generated ascorbic acid accumulation against a concentration gradient. Kinetics for the second component were indeterminate because ascorbate was not accumulated against a concentration gradient. Subcellular fractionation revealed that intracellular ascorbic acid in human B lymphocytes was >90% localized to the cytosol and not protein bound. Kinetic parameters of high-affinity ascorbic acid transport could operate effectively with plasma concentrations normally found in humans. (C) 1995 Academic Press, Inc.