烟酰胺腺嘌呤二核苷酸的氧化还原状态对深红红螺菌循环光合磷酸化的调节
Regulation of cyclic photophosphorylation in Rhodospirillum rubrum by the redox state of nicotinamide-adenine dinucleotide.
作者信息
Gimenez-Gallego G, Ramirez-Ponce M P, Ramirez J M
出版信息
Biochim Biophys Acta. 1979 Aug 14;547(2):211-7. doi: 10.1016/0005-2728(79)90004-5.
We have investigated the effect of the redox state of added NAD on the rates of anaerobic cyclic photophosphorylation which are supported by membrane vesicles isolated from Rhodospirillum rubrum. As the redox potential of NAD was lowered, the activity decreased according to a typical potentiometric titration. The Nernst plot showed an apparent midpoint potential (E'o) of -350 mV and had a slope which corresponded to a two-electron transition. Besides, an almost identical potentiometric relationship was found to exist between the extent of light-elicited ATP formation in anaerobic suspensions of intact R. rubrum cells and the redox potential of intracellular NAD. These results suggest that physiological photophosphorylation in R. rubrum requires the oxidized form of a membrane-bound constituent (E'o = -350 mV) whose redox state is controlled by the redox state of cytoplasmic NAD.
我们研究了添加的烟酰胺腺嘌呤二核苷酸（NAD）的氧化还原状态对由深红红螺菌分离出的膜囊泡所支持的厌氧循环光合磷酸化速率的影响。随着NAD氧化还原电位的降低，活性按照典型的电位滴定法下降。能斯特图显示表观中点电位（E'o）为-350 mV，且斜率对应于双电子转移。此外，发现在完整的深红红螺菌细胞的厌氧悬浮液中光诱导的ATP形成程度与细胞内NAD的氧化还原电位之间存在几乎相同的电位关系。这些结果表明，深红红螺菌中的生理光合磷酸化需要一种膜结合成分的氧化形式（E'o = -350 mV），其氧化还原状态受细胞质NAD的氧化还原状态控制。
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