Arnon D I, Chain R K
Proc Natl Acad Sci U S A. 1975 Dec;72(12):4961-5. doi: 10.1073/pnas.72.12.4961.
Under aerobic conditions that are likely to prevail in chloroplasts in vivo, the optimal concentration of ferredoxin for cyclic photophosphorylation was found to be equal to that required for NADP reduction and about one-tenth of that needed for cyclic photophosphorylation under anaerobic conditions. In the presence of ferredoxin and NADP, cyclic photophosphorylation operated concurrently with noncyclic photophosphorylation, producing an ATP: NADPH ratio of about 1.5. The effective operation of ferredoxin-catalyzed cyclic photophosphorylation by itself required a curtailment of the electron flow from water which was accomplished experimentally by the use of either an inhibitor or far-red monochromatic light. An unexpected discovery was that the operation of cyclic photophosphorylation by itself was also regulated by a back reaction of NADPH and ferredoxin with two components of chloroplast membranes, component C550 and cytochrome b559. The significance of these findings to photosynthesis in vivo is discussed.
在叶绿体体内可能普遍存在的有氧条件下，发现循环光合磷酸化的铁氧还蛋白最佳浓度等于NADP还原所需的浓度，约为厌氧条件下循环光合磷酸化所需浓度的十分之一。在铁氧还蛋白和NADP存在的情况下，循环光合磷酸化与非循环光合磷酸化同时进行，产生的ATP：NADPH比率约为1.5。铁氧还蛋白催化的循环光合磷酸化自身的有效运行需要减少来自水的电子流，这可通过使用抑制剂或远红光单色光在实验中实现。一个意外的发现是，循环光合磷酸化自身的运行也受NADPH和铁氧还蛋白与叶绿体膜的两个组分（C550组分和细胞色素b559）的逆反应调节。讨论了这些发现对体内光合作用的意义。
