RESPONSE TO PHOSPHATE DEPRIVATION IN BRASSICA-NIGRA SUSPENSION CELLS - ENHANCEMENT OF INTRACELLULAR, CELL-SURFACE, AND SECRETED PHOSPHATASE-ACTIVITIES COMPARED TO INCREASES IN PI-ABSORPTION RATE
RESPONSE TO PHOSPHATE DEPRIVATION IN BRASSICA-NIGRA SUSPENSION CELLS - ENHANCEMENT OF INTRACELLULAR, CELL-SURFACE, AND SECRETED PHOSPHATASE-ACTIVITIES COMPARED TO INCREASES IN PI-ABSORPTION RATE
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DOI：
10.1104/pp.93.2.504
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发表时间：
1990-06-01
期刊：
影响因子：
7.4
通讯作者：
PLAXTON, WC
中科院分区：
文献类型：
--
作者：
LEFEBVRE, DD;DUFF, SMG;PLAXTON, WC
黑芥悬浮细胞对缺磷的反应是通过增加其磷内流的潜力和提高细胞内、细胞表面和分泌的酸性磷酸酶的活性水平。然而，这些反应在时间上是不同的。在基础生长培养基中培养7天期间，磷酸盐流入能力增加15倍，同时内源性Pi减少10倍。与此相反，细胞内和细胞表面磷酸酶活性的变化后，细胞磷状态的改变已经到位了数天。即使在营养充足的细胞中，磷酸酶的分泌仍然相对较高，其他磷酸酶的活性也是如此。细胞表面酸性磷酸酶的Km值约为流入过程的10倍，而Escherichia coli是这种磷酸酶活性的强得多的抑制剂。从这些结果看来，磷的吸收和磷酸酶的活化的生产以不同的方式进行调节。此外，在Pi缺乏的条件下，黑芥细胞对Pi的吸收似乎并不直接涉及细胞表面磷酸酶。
Suspension cells of Brassica nigra responded to Pi deprivation by increasing their potential for Pi influx and by raising the active levels of intracellular, cell surface, and secreted acid phosphatases. These responses, however, were temporally distinct. Phosphate influx capacity increased 15-fold in parallel to a 10-fold decrease in endogenous Pi during 7 days of culture in basal growth medium. In contrast, intracellular and cell surface phosphatase activities changed only after alterations in cellular phosphorus status had been in place for a number of days. Even in nutrient sufficient cells the secretion of phosphatase remained relatively high as did the activities of the other phosphatases. The cell surface acid phosphatase had a Km of approximately 10 times that of the influx process and molybdate was a much stronger inhibitor of this phosphatase activity. From these results it appears that Pi absorption and the production of activation of phosphatases are regulated in a distinct manner. In addition, Pi uptake into Brassica nigra cells does not appear to directly involve the cell surface phosphatase under Pi-deficient conditions.