FEBS Letters | |
Demonstration of ΔpH‐ and Δψ‐induced synthesis of inorganic pyrophosphate in chromatophores from Rhodospirillum rubrum | |
Karlsson, Inga-Maj1  Strid, Åke1  Baltscheffsky, Margareta1  | |
[1] Institutionen för Biokemi, Arrheniuslaboratoriet, Stockholms Universitet, S-106 91 Stockholm, Sweden | |
关键词: Acid-base jump; Bioluminescence; H+-ATPase; H+-Pyrophosphatase; K+-diffusion potential; (Rhodospirillum rubrum); | |
DOI : 10.1016/0014-5793(87)80482-9 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
It is possible to obtain synthesis of PPi by artifical ion potentials in Rhodospirillum rubrum chromatophores. PPi can be formed by K+-diffusion gradients (Δψ), H+ gradients (ΔpH) or a combination of both. In contrast, ATP can only be synthesized by imposed Δψ or Δψ+ΔpH. For ATP formation there is also a threshold value of K+ concentration below which synthesis of ATP is not possible. Such a threshold is not found for PPi formation. Both PPi and ATP syntheses are abolished by addition of FCCP or nigericin and only marginally affected by electron transport inhibitors. The synthesis of PPi can be monitored for several minutes before it ceases, while ATP production stops within 30 s. As a result the maximal yield of PPi is 200 nmol PPi/μmol BChl, while that of ATP is no more than 25 nmol ATP/μmol BChl. The initial rates of syntheses were 0.50 μmol PPi/μmol BChl per min and 2.0 μmol ATP/μmol per min, respectively. These rates are approx. 50 and 20% of the respective photophosphorylation rates under saturating illumination.
【 授权许可】
Unknown
【 预 览 】
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