Greenfield N J, Hussain M, Lenard J
University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Department of Physiology and Biophysics, Piscataway.
Biochim Biophys Acta. 1987 Dec 7;926(3):205-14. doi: 10.1016/0304-4165(87)90205-4.
The vacuoles of logarithmic and stationary stage cells were compared by 31P-NMR with regard to pH, orthophosphate (Pi) content and average size of polyphosphate. The vacuoles of stationary cells had lower pH, higher Pi content, and polyphosphates of longer average chain length, although total polyphosphate content was about the same as in logarithmic cells. The lower vacuolar pH in stationary cells was the major cause of a larger cytoplasmic-vacuolar pH gradient. Addition of NH4Cl, (NH4)2SO4, methylamine or amantadine at pH 8 to cells in either stage caused an increase in both cytoplasmic and vacuolar pH, with little or no change in the cytoplasmic-vacuolar pH gradient. However, the administration of ammonium salts to the cells at pH 8.0 resulted in rapid hydrolysis of the intravacuolar polyphosphate to tripolyphosphate and Pi, with attendant redistribution of Pi between the vacuolar and cytoplasmic compartments.
通过31P-NMR对对数期和稳定期细胞的液泡在pH值、正磷酸盐（Pi）含量和多聚磷酸盐平均大小方面进行了比较。稳定期细胞的液泡pH值较低、Pi含量较高，且多聚磷酸盐的平均链长更长，尽管总多聚磷酸盐含量与对数期细胞大致相同。稳定期细胞中较低的液泡pH值是细胞质-液泡pH梯度较大的主要原因。在pH 8时向处于任一阶段的细胞添加NH4Cl、(NH4)2SO4、甲胺或金刚烷会导致细胞质和液泡pH值均升高，而细胞质-液泡pH梯度几乎没有变化。然而，在pH 8.0时向细胞施用铵盐会导致液泡内多聚磷酸盐迅速水解为三聚磷酸盐和Pi，同时Pi在液泡和细胞质区室之间重新分布。
