ATP POOLS AND TRANSIENTS IN BLUE-GREEN-ALGA, ANABAENA-CYLINDRICA
ATP POOLS AND TRANSIENTS IN BLUE-GREEN-ALGA, ANABAENA-CYLINDRICA
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DOI：
10.1007/bf00454849
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发表时间：
1976-01-01
影响因子：
2.8
通讯作者：
STEWART, WDP
中科院分区：
文献类型：
--
作者：
BOTTOMLEY, PJ;STEWART, WDP
A.在稳态连续培养物中生长的柱孢霉具有可提取的ATP库，其基于165 ± 0.001 μ g/ml的胰蛋白酶-荧光素酶测定来测量。35 nmol ATP/mg chl[叶绿素]a-1。该池由ATP合成速率和ATP利用速率之间的动态平衡维持。能够在短期内维持该池的磷酸化机制是总磷酸化、循环磷酸化和氧化磷酸化。根据环境条件，ATP酶可以通过从这些磷酸化机制中的一种快速切换到另一种来维持其ATP池。在每次切换时，ATP池中会有几秒钟的短暂下降。在切换到仅底物水平磷酸化起作用的条件下，ATP池福尔斯立即下降，但需要几个小时才能恢复。通过全磷酸化和环磷酸化的ATP合成的表观速率都高得多（210 ± 0.01）。30和250 .+-. 13 μ mol ATP/mg chla-1h-1）比通过氧化磷酸化的ATP合成的表观速率（22 ± 10 μ mol ATP/mg chla-1h-1）高。3 μ mol ATP/mg chla-1 h-1）。在长期实验中，ATP池在总磷酸化作用时得以维持。在缺乏光系统II活性或内源性C化合物的情况下，它不能通过单独的环状磷酸化或在缺乏内源性C化合物的情况下通过氧化磷酸化长期维持。ATP，ADP和AMP的测量表明，腺苷酸的总池是相似的，在短期内在光和黑暗中。在暗厌氧条件下，只有糖酵解和底物磷酸化可以进行，这表明这些过程在A中提供ATP的意义有限。圆柱形的
A. cylindrica grown in steady state continuous culture has an extractable ATP pool, measured on the basis of the luciferin-luciferase assay of 165 .+-. 35 nmol ATP/mg chl[chlorophyll]a-1. This pool is maintained by a dynamic balance between the rate of ATP synthesis and the rate of ATP utilization. Phosphorylating mechanisms which can maintain the pool in the short term are total photophosphorylation, cyclic photophosphorylation and oxidative phosphorylation. The alga can maintain its ATP pool by switching rapidly from 1 of these phosphorylating mechanisms to another depending on the environmental conditions. At each switch-over there is a transient drop in the ATP pool for a few seconds. On switching to conditions where only substrate level phosphorylation operates, the ATP pool falls immediately, but takes several hours to recover. The apparent rates of ATP synthesis by total photophosphorylation and by cyclic photophosphorylation are both much higher (210 .+-. 30 and 250 .+-. 13 .mu.moles ATP/mg chla-1h-1 respectively) than the apparent rate of ATP synthesis by oxidative phosphorylation (22 .+-. 3 .mu.mol ATP/mg chla-1 h-1). In long term experiments the ATP pool is maintained when total photophosphorylation is operating. It cannot be maintained in the long term by cyclic photophosphorylation alone in the absence of photosystem II activity or endogenous C compounds, or by oxidative phosphorylation in the absence of endogenous C compounds. Measurements of ATP, ADP and AMP show that the total pool of adenylates is similar in the light and in the dark in the short term. There is only limited production of ATP under dark anaerobic conditions when glycolysis and substrate phosphorylation can operate which suggests that these processes are of limited significance in providing ATP in A. cylindrica.