Eraso P, Gancedo C
Departamento de Bioquímica, Facultad de Medicina UAM, Madrid, Spain.
FEBS Lett. 1987 Nov 16;224(1):187-92. doi: 10.1016/0014-5793(87)80445-3.
When yeast grows on media in which a final external pH lower than 4 is attained there is a 2-3-fold increase in plasma membrane ATPase activity. This acid-mediated activation produces a 2-fold increase in the ATPase affinity for ATP but does not modify its optimum pH. The acid-mediated activation is dependent on the stage of growth, only late logarithmic or stationary cells being capable of being activated by incubation in an acidic buffer. Only cells able to activate the ATPase maintain a constant internal pH when incubated in acidic buffers. It is concluded that acid-mediated activation of the plasma membrane ATPase is a mechanism of maintaining constant internal pH during growth of yeast on acid media.
当酵母在最终外部pH值低于4的培养基上生长时，质膜ATP酶活性会增加2至3倍。这种酸介导的激活使ATP酶对ATP的亲和力增加了2倍，但并未改变其最适pH值。酸介导的激活取决于生长阶段，只有对数后期或稳定期的细胞能够通过在酸性缓冲液中孵育而被激活。只有能够激活ATP酶的细胞在酸性缓冲液中孵育时才能维持恒定的内部pH值。结论是，酸介导的质膜ATP酶激活是酵母在酸性培养基上生长期间维持恒定内部pH值的一种机制。
